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Dermatology of anticoagulant use, whereas a diffuse rash in a patient on sulfa drugs, anticonvulsants, or some antimicrobials may aid the clinician in diagnosing Stevens-Johnson syndrome, drug reactions with eosinophilia and systemic symptoms, or toxic epidermal necrolysis.  EXAMINATION The patient should be gowned and in a room with adequate lighting and appropriate privacy to allow entire skin examination. Inspect all skin and mucosal surfaces, including hair, nails, scalp, and mucous mem branes. Then evaluate the specific skin lesions. A magnifying lens and a portable light are helpful aids. Examine the skin systematically. Determine the distribution, pattern, arrangement, morphology, extent, and evolutionary changes of the lesions. Distribution is the location of the skin findings, and the pattern is their anatomic, functional, and physiologic arrangement. For example, a unilateral band-like arrangement of lesions on the thorax suggests varicella-zoster virus infection. Skin diseases often present with a predilection for certain body areas; the distribution of lesions will assist in narrowing the diagnostic possibilities. From the anatomic perspective, the skin surfaces that are usually considered as separate areas of distribution are generalized body; face and scalp; trunk and axillae; groin and skin folds; and hands, feet, and nails. The extremities may be further subdivided into upper versus lower, proximal versus distal, wrists versus ankles, and hands versus feet. In a patient with diffuse erythema in whom toxic shock syndrome is suspected, identify the presence of a foreign body such as a retained tampon. Petechiae should prompt investigation for meningococcemia or Rocky Mountain spotted fever. Rashes on exposed portions of the skin should prompt inquiries about sun exposure, jewelry, topical agents, or exposures. See Table 248-1 for a differential diagnosis of skin lesions as a function of location, including both distribution and pattern considerations. Use the burn rule of nines (see Chapter 217, “Thermal Burns”) to estimate the degree of skin involvement in disorders with widespread distribution. This calculation also may be used to determine the amount of topical medication required for a specific treatment course or whether an oral medication might be more appropriate. Extensive erythroderma (often >90% of body surface area) is a dermatologic emergency, particularly when accompanied by a fever. Severe erythroderma can represent underlying severe infectious dermatitis, toxic shock syndrome, cutane ous T-cell lymphoma, drug reaction, psoriasis, or seborrheic dermatitis. Lesion arrangement refers to the symmetry and configuration. Bilateral symmetry suggests a systemic internal event or symmetric external exposure, as seen in erythema multiforme, with plaque-like lesions on the flexor surfaces of the extremities, or contact dermatitis related to a lotion application. An asymmetric arrangement supports a localized process. Configuration may apply to a single lesion with reference to its individual features or, alternatively, to multiple lesions and their relation to one another. For instance, internal configuration is illustrated by the relation between the central papule relative to the erythematous ring in the target lesion of erythema multiforme; on the total-body scale, configuration is demonstrated by clustering of lesions in a herpesvirus infection or by a linear arrangement as with a reaction from poison ivy or oak.

ration is illustrated by the relation between the central papule relative to the erythematous ring in the target lesion of erythema multiforme; on the total-body scale, configuration is demonstrated by clustering of lesions in a herpesvirus infection or by a linear arrangement as with a reaction from poison ivy or oak. Other terms used to describe the lesion configuration are listed in Table 248-2. Recognition of the primary lesion is vital in establishing the diagnosis; the use of the primary lesion’s morphology is very important regarding the generation of an appropriate differential diagnosis and ultimately the correct dermatologic diagnosis. The primary lesion is the one that has not been altered by secondary issues, including healing, complicating infection, medication application, or scratching. Examples of primary skin lesions are macules, papules, nodules, tumors, cysts, plaques, wheals, vesicles, bullae, and pustules. Careful attention should be paid Initial Evaluation and Management of Skin Disorders William Rushton William J. Brady INTRODUCTION Most dermatologic emergencies presenting to the ED involve skin lesions resulting from infections, irritants, and allergic etiologies, with a smaller subset related to malignancy. 1 Visual pattern recognition is the key to diagnosis. The recommended approach for the diagnosis of a skin disorder in the ED (assuming resuscitation or stabilization is not required) is to: 1. Determine the chief complaint. 2. Obtain a brief history (duration, rate of progression, and location of lesions). 3. Perform the dermatologic examination (morphology and extent of distribution). 4. Formulate the age-appropriate differential diagnosis based on lesion morphology and distribution. 5. Elicit additional concerns from the history (associated complaints, comorbidity, medications, or exposures), and include or exclude syndromes in the differential diagnosis based on this information. 6. Evaluate for systemic involvement, and consider ancillary investiga tions, if necessary. 7. Obtain dermatologic consultation, if necessary, and arrange for appropriate referral (primary care or dermatologic). DIAGNOSTIC APPROACH  HISTORY Determine the chief complaint and obtain a brief history (discomfort, duration, rate of progression, percentage of body surface involvement, and location of lesions). The secondary history should include issues relating to the lesion: morphology, evolutionary nature, rate of progression, and distribution. Associated systemic complaints and mucosal systems must be identified. Ask about exposures, immunizations, toxins, chemicals, foods, animals, insects, plants, and ill contacts. Review sexual history, if appropriate, and medical and family histories. If applicable, obtain a detailed occupational history as industrial exposure may be causative. Asking about medication use, sun exposure, travel history, or particular food ingestion also may yield helpful information. Be sure to include any other housemates or partners in your history of exposures; contact dermatitis can occur from exposure to fragrances or other products that a partner is using. 2 The patient should also be asked about the degree of discomfort of the dermatoses; a painful dermatitis is often a red flag and may not be associated with a self-limiting lesion. A detailed medication history is important, and particular atten tion should be paid to recently started drugs or dosage increases. Ery thema multiforme, exfoliative dermatitis, photosensitivity reactions, toxic epidermal necrolysis, and vasculitis are common medicationinduced drug reactions. Dermal necrosis should prompt consideration SECTION CHAPTER Tintinalli_Sec20_p1607-1668.indd 1607 8/2/19 7:23 PM

o recently started drugs or dosage increases. Ery thema multiforme, exfoliative dermatitis, photosensitivity reactions, toxic epidermal necrolysis, and vasculitis are common medicationinduced drug reactions. Dermal necrosis should prompt consideration SECTION CHAPTER Tintinalli_Sec20_p1607-1668.indd 1607 8/2/19 7:23 PM 1608 SECTION 20: Dermatology TABLE 248-2 Lesion Configuration Descriptors Descriptor Configuration Annular Ring-like or pertaining to the outer edge Arcuate Curved or pertaining to the curve Circinate Circular Confluent Blending together Dermatomal Belt-like or limited to one side of the body in anatomic dermatome Discoid Solid, round, slightly raised, or pertaining to a disk Discrete Separate or individual Grouped Clustered Guttate Scattered Gyrate Coiled or winding Herpetiform Creeping Iris Concentric circles Linear In a line Polycyclic Overlapping circles or borders of irregular curves Retiform Net-like Serpiginous Snake-like (Continued ) TABLE 248-1 Differential Diagnosis Relative to Lesion Distribution and Pattern Distribution and Pattern Differential Diagnosis Flexor surfaces Atopic dermatitis, candidiasis, eczema, ichthyosis Sun exposure (face, upper thorax, distal extremities) Sunburn, photosensitive drug eruption, photosensitive dermatitis, systemic lupus erythematosus, viral exanthem, porphyria Distal extremities Viral exanthem, atopic or contact dermatitis, eczema, Rocky Mountain spotted fever, gonococcemia Front and back of chest Pityriasis rosea, secondary syphilis, drug eruption, atopic or contact dermatitis, psoriasis Clothing covered (thorax and distal lower extremities) Contact dermatitis, psoriasis, folliculitis Acneiform (face and upper thorax) Acne, drug-induced acne, irritant dermatitides TABLE 248-3 Lesion Morphology (Continued ) Descriptor Morphology Lesion Nature Height Relative to Adjacent Skin Image Excoriation Linear marks from scratching Secondary Flat Erosion Ruptured vesicle or bulla with denuded epidermis Secondary Depressed to a nonblanching lesion. Secondary lesions have had their appearance altered due to disease evolution or various external factors, as noted earlier, and include crusts, scales, fissures, erosions, ulcerations, excoriations, atrophy, scarring, and lichenification. See Table 248-3 for a listing and descriptions of the various morphologic descriptors of dermato logic lesions; see Tables 248-4 and 248-5 for a differential diagnosis Tintinalli_Sec20_p1607-1668.indd 1608 8/2/19 7:23 PM

sts, scales, fissures, erosions, ulcerations, excoriations, atrophy, scarring, and lichenification. See Table 248-3 for a listing and descriptions of the various morphologic descriptors of dermato logic lesions; see Tables 248-4 and 248-5 for a differential diagnosis Tintinalli_Sec20_p1607-1668.indd 1608 8/2/19 7:23 PM CHAPTER 248: Initial Evaluation and Management of Skin Disorders 1609 TABLE 248-3 Lesion Morphology (Continued ) Descriptor Morphology Lesion Nature Height Relative to Adjacent Skin Image Fissure Linear cracks on skin surface Secondary Flat Ulcer Epidermal or dermal tissue loss Secondary Depressed Macule Flat, circumscribed discoloration ≤1 cm in diameter; color varies Primary Flat Petechiae Nonblanching purple spots <2 mm in diameter Primary Flat (Continued ) Tintinalli_Sec20_p1607-1668.indd 1609 8/2/19 7:23 PM 1610 SECTION 20: Dermatology TABLE 248-3 Lesion Morphology (Continued ) Descriptor Morphology Lesion Nature Height Relative to Adjacent Skin Image Sclerosis Firm, indurated skin Secondary Flat or elevated Telangiectasia Small, blanchable superficial capillaries Primary Flat Purpura Nonblanching purple discoloration of the skin Primary Flat Abscess Tender, erythematous, fluctuant nodule Primary Elevated (Continued ) Tintinalli_Sec20_p1607-1668.indd 1610 8/2/19 7:23 PM CHAPTER 248: Initial Evaluation and Management of Skin Disorders 1611 TABLE 248-3 Lesion Morphology (Continued ) Descriptor Morphology Lesion Nature Height Relative to Adjacent Skin Image Cyst Sack containing liquid or semisolid material Primary Elevated Nodule Palpable solid lesion <1 cm in diameter Primary Elevated Tumor Palpable solid lesion >1 cm in diameter Primary Elevated (Continued ) Tintinalli_Sec20_p1607-1668.indd 1611 8/2/19 7:23 PM 1612 SECTION 20: Dermatology TABLE 248-3 Lesion Morphology (Continued ) Descriptor Morphology Lesion Nature Height Relative to Adjacent Skin Image Scar Sclerotic area of skin Secondary Flat or elevated Wheal Transient, edematous papule or plaque with peripheral erythema Primary Flat or elevated Vesicle Circumscribed, thin-walled, elevated blister <5 mm in diameter Primary Elevated (Continued ) Tintinalli_Sec20_p1607-1668.indd 1612 8/2/19 7:23 PM

jacent Skin Image Scar Sclerotic area of skin Secondary Flat or elevated Wheal Transient, edematous papule or plaque with peripheral erythema Primary Flat or elevated Vesicle Circumscribed, thin-walled, elevated blister <5 mm in diameter Primary Elevated (Continued ) Tintinalli_Sec20_p1607-1668.indd 1612 8/2/19 7:23 PM CHAPTER 248: Initial Evaluation and Management of Skin Disorders 1613 TABLE 248-3 Lesion Morphology (Continued ) Descriptor Morphology Lesion Nature Height Relative to Adjacent Skin Image Bulla Circumscribed, thin-walled, elevated blister >5 mm in diameter Primary Elevated Pustule Vesicle containing purulent fluid Primary Elevated Papule Elevated, solid, palpable lesion <1 cm in diameter; color varies Primary Elevated (Continued ) Tintinalli_Sec20_p1607-1668.indd 1613 8/2/19 7:23 PM 1614 SECTION 20: Dermatology TABLE 248-3 Lesion Morphology (Continued ) Descriptor Morphology Lesion Nature Height Relative to Adjacent Skin Image Plaque Flat-topped elevation formed by confluence of papules >0.5 cm in diameter Primary Elevated Comedo Papule with an impacted pilosebaceous unit Primary Elevated Source: Images reproduced with permission from Wolff KL, Johnson R, Suurmond R: Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. © 2005, McGraw-Hill, Inc., New York; and Fleischer AB Jr, Feldman SR, McConnell CF, et al: Emergency Dermatology: A Rapid Treatment Guide. © 2002, McGraw-Hill, Inc., New York. of the various skin disorders relative to primary and secondary lesion morphologies. DIAGNOSTIC TECHNIQUES A potassium hydroxide preparation is used in patients with suspected molluscum contagiosum and dermatophytic infections. The test is performed on loose skin scales, nail parings, subungual debris, short residual hairs, or small pearly globules (from a molluscum body). Test steps are in Table 248-6. The material is then viewed under a microscope at low power, with the condenser and light at low levels. As the slide is scanned, rapidly focus up and down. True hyphae ( Figure 248-1), seen in dermato phytic infections, are long, branching, green rods of constant width that cross the borders of epithelial cells. Molluscum bodies are oval discs with homogeneous cytoplasm ( Figure 248-2). In hair fragments, Tintinalli_Sec20_p1607-1668.indd 1614 8/2/19 7:23 PM

s up and down. True hyphae ( Figure 248-1), seen in dermato phytic infections, are long, branching, green rods of constant width that cross the borders of epithelial cells. Molluscum bodies are oval discs with homogeneous cytoplasm ( Figure 248-2). In hair fragments, Tintinalli_Sec20_p1607-1668.indd 1614 8/2/19 7:23 PM CHAPTER 248: Initial Evaluation and Management of Skin Disorders 1615 TABLE 248-4 Differential Diagnosis of Selected Skin Disorders Relative to Primary Lesion Morphology* ( Continued ) Lesion Morphology Differential Considerations Images Macule Drug eruption (fixed or photosensitive), nevus, tattoo (ink), rheumatic fever, syphilis (secondary), viral exanthema, toxic or infectious erythemas, meningococcemia (early), external trauma (ecchymosis), vitiligo, tinea versicolor, cellulitis (early) Papule Acne, basal cell carcinoma, melanoma, nevus, warts, molluscum conta giosum, skin tags, atopic dermatitis, urticaria, eczema, folliculitis, insect bites, vasculitis, psoriasis, scabies, Toxicodendron dermatitis (poison ivy, oak, sumac), erythema multiforme, varicella (early), gonococcemia Plaque Eczema, pityriasis rosea, tinea corporis and versicolor, psoriasis, seborrheic dermatitis, urticaria, syphilis (secondary), erythema multiforme (Continued ) Tintinalli_Sec20_p1607-1668.indd 1615 8/2/19 7:23 PM 1616 SECTION 20: Dermatology TABLE 248-4 Differential Diagnosis of Selected Skin Disorders Relative to Primary Lesion Morphology* ( Continued ) Lesion Morphology Differential Considerations Images Nodule Basal cell, squamous cell, or metastatic carcinoma; melanoma; erythema nodosum; furuncle; lipoma; warts Wheal Urticaria, angioedema, insect bites, erythema multiforme Pustule Acne, folliculitis, gonococcemia, hidradenitis suppurativa, herpetic infection (herpes simplex, herpes zoster, varicella), impetigo, psoriasis, rosacea, pyoderma gangrenosum (Continued ) Tintinalli_Sec20_p1607-1668.indd 1616 8/2/19 7:24 PM

ma; warts Wheal Urticaria, angioedema, insect bites, erythema multiforme Pustule Acne, folliculitis, gonococcemia, hidradenitis suppurativa, herpetic infection (herpes simplex, herpes zoster, varicella), impetigo, psoriasis, rosacea, pyoderma gangrenosum (Continued ) Tintinalli_Sec20_p1607-1668.indd 1616 8/2/19 7:24 PM CHAPTER 248: Initial Evaluation and Management of Skin Disorders 1617 TABLE 248-4 Differential Diagnosis of Selected Skin Disorders Relative to Primary Lesion Morphology* ( Continued ) Lesion Morphology Differential Considerations Images Vesicle Herpetic infection (herpes simplex, herpes zoster, varicella), impetigo, Toxicodendron dermatitis (poison ivy, oak, sumac), thermal burn, friction blister, toxic epidermal necrolysis, bullous pemphigoid, pemphigus vulgaris Bulla Bullous impetigo, Toxicodendron dermatitis (poison ivy, oak, sumac), thermal burn, friction blister, toxic epidermal necrolysis, bullous pemphigoid, pemphigus vulgaris *This list is not exhaustive, but it represents the more common syndromes likely to be encountered by the emergency physician. Source: Images reproduced with permission from Wolff KL, Johnson R, Suurmond R: Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. © 2005, McGraw-Hill, Inc., New York; and Fleischer AB Jr, Feldman SR, McConnell CF, et al: Emergency Dermatology: A Rapid Treatment Guide. © 2002, McGraw-Hill, Inc., New York. the organisms appear as small, round spores packed closely within the hair shaft. Scabies and lice preparations are useful in patients with possible infestation. In scabies infestations, the rash itself may resemble other dermatologic syndromes; microscopic analysis will confirm the diagnosis. The donor site for skin specimen selection is very important. The best sites include burrows (10 mm, elongated papule with a pustule or vesicle) and papules on the fingers, wrists, and elbows ( Figure 248-3). Within the vesicle or pustule, a small black dot is noted, which is the mite. The point of the scalpel is scraped across the lesion while hold ing the skin taut; the mite is then removed. A single drop of mineral oil may be applied to the blade to ensure that the scrapings adhere to the instrument. The material is then placed on the microscope slide with an additional drop of mineral oil; gentle pressure on the coverslip will flat ten thick specimens. Using low power, the slide is scanned for presence of the mite, eggs, or feces. Mites are eight-legged creatures that are easily identified on thin smears; thick specimens may require additional viewing to look for the mite. Additional findings supportive of the diagnosis include eggs (smooth ovals) and feces (clusters of red-brown pellets; Figure 248-4). Lice are usually found on the scalp, eyelashes, and pubic areas and may be visible to the unaided eye ( Figure 248-5). The Tzanck smear, useful in blistering disorders, assists in establish ing the diagnosis of a herpes infection: herpes simplex, herpes zoster, and varicella. The choice material for examination is obtained from the Tintinalli_Sec20_p1607-1668.indd 1617 8/2/19 7:24 PM

d may be visible to the unaided eye ( Figure 248-5). The Tzanck smear, useful in blistering disorders, assists in establish ing the diagnosis of a herpes infection: herpes simplex, herpes zoster, and varicella. The choice material for examination is obtained from the Tintinalli_Sec20_p1607-1668.indd 1617 8/2/19 7:24 PM 1618 SECTION 20: Dermatology TABLE 248-5 Differential Diagnosis of Selected Skin Disorders Relative to Secondary Lesion Morphology* Lesion Morphology Differential Considerations Images Scales Psoriasis, pityriasis rosea, toxic and infectious erythemas, syphilis (secondary), dermatophytic infection (tinea), tinea versicolor, xerosis (dry skin), thermal burn (first degree) Crusts Eczema, dermatophytic infection (tinea), impetigo, contact dermatitis, insect bite Erosions Candidiasis, dermatophytic infection (tinea), eczema, toxic epidermal necroly sis, toxic-infectious erythemas, erythema multiforme, primary blistering disorders (bullous pemphigoid and pemphigus vulgaris), brown recluse spider envenomation Ulcers Aphthous lesions, chancroid, decubitus ulcer, thermal or friction injury, sub acute or chronic ischemia, malignancy, chancre (primary syphilis), primary blis tering disorders (bullous pemphigoid and pemphigus vulgaris), brown recluse spider envenomation, pyoderma gangrenosum, stasis ulcer, factitial ulcer *This list is not exhaustive, but it represents the more common syndromes likely to be encountered by the emergency physician. Source: Images reproduced with permission from Wolff KL, Johnson R, Suurmond R: Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. © 2005, McGraw-Hill, Inc., New York; and Fleischer AB Jr, Feldman SR, McConnell CF, et al: Emergency Dermatology: A Rapid Treatment Guide. © 2002, McGraw-Hill, Inc., New York. Tintinalli_Sec20_p1607-1668.indd 1618 8/2/19 7:24 PM

ohnson R, Suurmond R: Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. © 2005, McGraw-Hill, Inc., New York; and Fleischer AB Jr, Feldman SR, McConnell CF, et al: Emergency Dermatology: A Rapid Treatment Guide. © 2002, McGraw-Hill, Inc., New York. Tintinalli_Sec20_p1607-1668.indd 1618 8/2/19 7:24 PM CHAPTER 248: Initial Evaluation and Management of Skin Disorders 1619 base of a recently unroofed lesion; purulent fluid at the base of the lesion is removed with a scalpel and placed on a microscope slide. The material is allowed to air dry and then is stained with Giemsa or Wright stain. Using low power, the slide is scanned for epithelial cells. Multinucleated giant cells (Figure 248-6 ), indicative of a herpes infection, are a syncy tium of epidermal cells with multiple overlapping nuclei. The presence of the multinucleated giant cell does not distinguish between herpes simplex, herpes zoster, and varicella syndromes. Wood’s light examination is helpful in several different situations, including erythrasma (a superficial Corynebacterium infection of moist skin in the groin, axilla, and web spaces), fungal infections caused by Malassezia species or Microsporum species, certain pseudomonal skin infections, and porphyria cutanea tarda. Wood’s light is an ultraviolet source that emits light at a wavelength of 365 nm. The following fluo rescent findings are noted in these conditions: erythrasma, red or pink; tinea, green or yellow; Pseudomonas , yellow or green; and porphyria cutanea tarda, urine fluoresces orange or red. Ancillary studies may also be required to assess for systemic involvement. Fever and leukocytosis may be indicative of an underlying infectious disorder or an underlying autoimmune reaction. In patients on anticonvulsants, elevated transaminases may represent underlying DRESS syndrome (drug reaction with eosinophilia and systemic symptoms). Furthermore, disseminated intravascular coagulation, thrombocytopenia, and acute kidney injury may alert the astute clinician to underlying bacteremia or toxic shock syndrome. 3 Imaging may be required to rule out foreign bodies or to assess the depth of tissue involvement in conditions such as Fournier’s gangrene. ED TREATMENT  SYSTEMIC CORTICOSTEROIDS Systemic corticosteroids are the treatment of choice for some general ized conditions and are discussed in the chapters dealing with specific diagnoses. Some severe widespread dermatologic syndromes, such as erythema multiforme, toxic epidermal necrolysis, and vasculitis, are best treated with systemic steroids only after consultation with a dermatologist. Other disorders, including urticaria, angioedema, Toxicodendron dermatitis (rhus, poison ivy, or poison oak), and other contact or allergic FIGURE 248-1. Hyphae in scraping from tinea pedis. [Photo contributed by University of North Carolina Department of Dermatology.] FIGURE 248-2. Molluscum bodies. [Reproduced with permission from the Centers for Disease Control and Prevention Public Health Image Library: http://phil.cdc.gov/phil/home.asp.] TABLE 248-6 Potassium Hydroxide (KOH) Examination •  Collect  scale with a scalpel edge, place in small heap on slide, cover with coverslip. •  Apply  KOH 10%–40% solution to edge of coverslip; it will be drawn under coverslip. •  Apply  heat to underside of slide (match or lighter) until bubbles appear under coverslip. •  Visualize  under 10× magnification. FIGURE 248-3. Classic burrows of scabies. [Reproduced with permission from Fleischer AB Jr, Feldman SR, McConnell CF, et al: Emergency Dermatology: A Rapid Treatment Guide. © 2002, McGraw-Hill, Inc., New York.] Tintinalli_Sec20_p1607-1668.indd 1619 8/2/19 7:24 PM

under coverslip. •  Visualize  under 10× magnification. FIGURE 248-3. Classic burrows of scabies. [Reproduced with permission from Fleischer AB Jr, Feldman SR, McConnell CF, et al: Emergency Dermatology: A Rapid Treatment Guide. © 2002, McGraw-Hill, Inc., New York.] Tintinalli_Sec20_p1607-1668.indd 1619 8/2/19 7:24 PM 1620 SECTION 20: Dermatology FIGURE 248-4. Microscopic view of a scabies mite with visible eggs and feces. [Reproduced with permission from Wolff KL, Johnson R, Suurmond R: Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. © 2005, McGraw-Hill, Inc., New York.] FIGURE 248-5. Adult head lice. [Reproduced with permission from the Centers for Dis ease Control and Prevention Public Health Image Library: http://phil.cdc.gov/phil/home.asp.] disorders, are potential indications for systemic corticosteroids when an extensive area of skin is involved. Patients with severe disease can see significant relief with oral corticosteroids within 12 to 24 hours. Patients with poison ivy or oak eruptions who require systemic steroids should be treated with oral prednisone (1 milligram/kg body weight) for 2 weeks. 5 Other contact or allergic dermatitides may benefit from an abbreviated course (4 days) of oral prednisone. Efficacy of a short course of corticosteroids in addition to antihistamines remains controversial. A 1995 randomized controlled study showed improvement within 48 hours with 20 milligrams of prednisone twice a day for a total of 5 days. A more recent randomized trial, however, showed no difference with 40 milligrams of prednisone daily for 4 days. 7 Expert guidelines still recommend prednisone for refractory cases of acute urticaria, although specific doses and duration are not well defined. 8 However, oral corticosteroids are relatively contraindicated, or must be used with great care in those with diabetes, hypertension, active peptic ulcer disease, psychiatric disease, and immunodeficiency. Follow-up within 2 to 3 days with the primary care physician or a dermatologist is needed if oral cortico steroids are prescribed to patients with these comorbidities.  TOPICAL CORTICOSTEROIDS Topical corticosteroids are powerful and useful tools in the management of dermatologic disease. Numerous agents are available for use. They differ in concentration, base components, and cost. Familiarity with a single FIGURE 248-6. Tzanck smear under microscopy showing a multinucleated giant cell, indicative of a herpetic infection. [Reproduced with permission from Wolff KL, Johnson R, Suurmond R: Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. © 2005, McGraw-Hill, Inc., New York.] Tintinalli_Sec20_p1607-1668.indd 1620 8/2/19 7:24 PM

ear under microscopy showing a multinucleated giant cell, indicative of a herpetic infection. [Reproduced with permission from Wolff KL, Johnson R, Suurmond R: Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 5th ed. © 2005, McGraw-Hill, Inc., New York.] Tintinalli_Sec20_p1607-1668.indd 1620 8/2/19 7:24 PM CHAPTER 248: Initial Evaluation and Management of Skin Disorders 1621 agent in each potency class is sufficient to treat any steroid-responsive skin ailment safely and effectively. Corticosteroid potency or strength (i.e., the anti-inflammatory property) is measured by the agent’s ability to induce vasoconstriction. Agents’ strengths are rated by vasoconstricting ability on a scale of 1 to 7; group 1 agents are the most powerful corticosteroids, and group 7 medications are the least potent ( Table 248-7). In general, ointments are more potent than creams or lotions. Topical Corticosteroid Strength Marked variation in potency is seen across various corticosteroids, whereas much smaller differences in strength are encountered for different concentrations of individ ual agents. Many corticosteroids are fluorinated. Fluorination greatly increases the potency, but also increases the risk of adverse reactions, and fluorinated formulations should not be used in pregnancy . Use of the appropriate-strength topical steroid is strongly encouraged at the start of therapy. Starting with a less powerful agent is not likely to spare the patient from potential adverse effects or to produce adequate control of the disease. Hydrocortisone, perhaps the most frequently used topical corticosteroid in the outpatient setting, is available over the counter in strengths up to 1% and by prescription in strengths to a maximum of 2.5%. Hydrocortisone is safe and may be used on most body surfaces, including the face, genitalia, flexure creases, and intertriginous zones. It also is safe for use in infants and children. For the treatment of diseases involving the palms and soles, hydrocortisone is a poor choice, because the thickened skin does not allow adequate penetration of this relatively low-potency steroid. Corticosteroids of moderate potency, including triamcinolone acetonide and fluocinolone acetonide , are useful in treating severely inflamed skin and the thicker skin of the scalp, trunk, extensor surfaces, palms, and soles. These agents should not be applied to the face or genitals or used in infants because of the risk of skin atrophy. See Table 248-8 for recommendations on the potency of corticosteroid to use in treating various dermatologic diseases. When using agents found in group 6 or 7, consultation with a dermatologist may be advised. Different skin surfaces respond differently to topical corticosteroid therapy; this differential response relates to the absorption of the ste roid into the deeper tissues. The relatively thin skin surfaces of the face respond very rapidly to the use of group 7 agents, whereas the thicker skin of the palms and soles requires a highly potent steroid. Irritations for which a low-potency agent may provide the same treatment effec tiveness as a higher potency agent include those involving raw, inflamed skin (such skin absorbs medication more rapidly and readily); treatment regions with skin surfaces in frequent contact, such as intertriginous areas (the apposition of two skin surfaces produces enhanced absorption of drug, similar to the effect of an occlusive dressing); and areas of skin under tight clothing, such as the diaper area (absorption of the agent is enhanced due to the occlusive effect of the garment). In general, lower potency agents are acceptable in these situations. Application of Topical Steroids The application of creams, oint ments, gels, and lotions is relatively straightforward.

kin under tight clothing, such as the diaper area (absorption of the agent is enhanced due to the occlusive effect of the garment). In general, lower potency agents are acceptable in these situations. Application of Topical Steroids The application of creams, oint ments, gels, and lotions is relatively straightforward. The medication is applied in a thin layer and should be massaged daily into the skin, as directed. Washing the skin before corticosteroid application is unnec essary. Advise patients to follow directions closely both early and late in the treatment course. Using extra medication per dose or applying medication more frequently early in the treatment period is not desir able; likewise, reducing the frequency of application or decreasing the amount of medication as the disease process responds to therapy can cause relapse. Optimal application regimens have not been determined for topical corticosteroids in most dermatologic syndromes. The more potent agents are best applied two to three times daily for 1 to 2 weeks followed by a drug-free week; additional therapy may be required as determined by the disease and by the particular patient’s response to the initial therapy. Agents from the less potent steroid groups may be applied three times daily for 2 to 4 weeks followed by a 7-day steroidfree period. Prescribing the Correct Amount of Topical Steroid Determining the correct amount of topical steroid to prescribe is at times difficult. TABLE 248-7 Examples of Topical Corticosteroid Agents by Potency Group* U.S. Classification British Classification Representative Topical Agent Formulation 1: Superpotent 1: Very Potent Clobetasol (Temovate, Clobex) Halobetasol (Halonate, Ultravate) Betamethasone (Diprolene) 0.05% cream or ointment 2: Potent 2: Potent Fluocinonide (Lidex, Vanos) Halcinonide (Halog) Mometasone (Elocon) 0.05% ointment 0.1% cream 0.1% ointment 3: Upper mid-strength Betamethasone (Diprolene) Fluticasone (Cutivate) Triamcinolone (Kenalog) 0.05% lotion 0.005% ointment 0.1% ointment 4: Mid-strength Mometasone (Elocon) 0.1% cream, lotion 5: Lower mid-strength 3: Moderate Betamethasone (Diprolene) Fluocinolone (Synalar) Fluticasone (Cutivate) 0.1% cream 0.025% cream 0.05% cream 6: Mild Alclometasone (Alclovate) Desonide (Desonate, Desocort) Triamcinolone (Kenalog) 0.05% cream or ointment 0.05% cream 0.025% cream 7: Least Potent 4: Mild Hydrocortisone 1% or 2.5% cream, lotion or ointment Note: Trade names vary. Strength classification can vary. Strength also depends upon the product itself, amount applied, and nature of skin at the application site. *Preparations are listed by U.S. and British potency groups: Group 1 is most potent; group 7 (British 4) is least potent. TABLE 248-8 Recommended Corticosteroid Potency for Treatment of Various Dermatologic Diseases Groups 1 and 2 Groups 3 to 5 Groups 6 and 7 Psoriasis Atopic dermatitis Nonspecific dermatitis of face, eyelids, and perineum Eczema of hand (severe) Stasis dermatitis Poison ivy dermatitis (severe) Seborrheic dermatitis Tinea Atopic dermatitis (severe) Scabies Nonspecific dermatitis of face (severe) Tintinalli_Sec20_p1607-1668.indd 1621 8/2/19 7:24 PM

s 6 and 7 Psoriasis Atopic dermatitis Nonspecific dermatitis of face, eyelids, and perineum Eczema of hand (severe) Stasis dermatitis Poison ivy dermatitis (severe) Seborrheic dermatitis Tinea Atopic dermatitis (severe) Scabies Nonspecific dermatitis of face (severe) Tintinalli_Sec20_p1607-1668.indd 1621 8/2/19 7:24 PM 1622 SECTION 20: Dermatology The burn rule of nines may be used to estimate the amount of topical corticosteroid to prescribe. Calculate the percentage of body surface area requiring therapy and then multiply the percentage by a correction factor of 30. This calculation provides the amount of topical corticoste roid in grams for a single application. Next, determine the number of administrations required in the treatment course. For example, a threetimes-daily regimen for a duration of 10 days requires 30 applications. The number of applications is multiplied by the grams required for a single dose to yield the total amount to be prescribed ( Table 248-9). In general, 9 grams of topical steroid cover 9% of the body surface area for 1 day with a thrice-daily application. See Table 248-10 for a description of the amount of topical corticosteroid to be dispensed relative to the coverage area and duration of therapy. Avoid Tachyphylaxis Tachyphylaxis refers to the decrease in respon siveness to a drug as a result of enzyme-mediated events. The term is used in relation to topical corticosteroids to describe the early development of tolerance to vasoconstricting ability. In general, vasoconstriction has been demonstrated to decrease progressively over time after a topical steroid has been applied. Such reductions in strength due to tolerance are encountered as soon as 4 days into the treatment course in all potency groups, but are thought to be more important for corticosteroids in groups 1 and 2. A reasonable strategy to counter the development of tachyphylaxis is the use of interrupted application schedules. An interrupted treatment course might include an initial three-times-daily application for 2 weeks, followed by 1 week without use of the drug, and then a repeat of the cycle.  ANTIHISTAMINES Antihistamines (histamine-1 antagonists) are frequently used in clinical practice to control pruritus. These drugs include first-generation antihistamines such as diphenhydramine and hydroxyzine as well as second-generation antihistamine agents, including astemizole, cetirizine, fexofenadine, and loratadine. 9-11 Second-generation histamine-1 antihistamines, while purporting a longer duration of action, do not have the therapeutic sedation found in the first-generation class. Placebo effect and verbal cues have also been implicated in reducing pruritus. 12 True refractory cases of pruritus may require drugs treating anti–immunoglobulin E antibodies, mast cell modulators, mast cell mediator blockers, and immunomodulators; however, consultation with a dermatology expert is advised before commencement of these agents. The use of topical antihistamine preparations is discouraged, because these agents are readily absorbed and dosing is difficult to predict. See Table 248-11 for suggested dosing, administration schedules, and routes of therapy for these antihistamines. Histamine-2 antagonists (ranitidine or famotidine) also have demonstrated some benefit in patients with a true histamine allergic-mediated event, in particular urticaria, and TABLE 248-9 Determination of the Correct Amount When Prescribing Topical Steroids •  Use  burn rule of nines to determine percentage of body surface area affected. •  Percentage  of body surface area × 30 = grams of topical corticosteroid per application. •  Application times per day × number of days of treatment = total number of applications.

of the Correct Amount When Prescribing Topical Steroids •  Use  burn rule of nines to determine percentage of body surface area affected. •  Percentage  of body surface area × 30 = grams of topical corticosteroid per application. •  Application times per day × number of days of treatment = total number of applications. •  Total grams to prescribe = [% body surface area × 30] × [times per day × number of days]. TABLE 248-10 Amount of Corticosteroid Cream to Dispense* Body Area Suggested Potency Amount to Dispense (grams) Face Low   45 Arm Intermediate or low 90 Leg Intermediate or low 180 Hand or foot Intermediate or low   45 Forearm Intermediate or low   45 Chest or back Intermediate or low 180 *Based on application three times a day for 10 days of therapy. TABLE 248-11 Antihistamines Useful in the Management of Dermatologic Disease Medication (trade name) Adult Dosage Pediatric Dosage Diphenhydramine (Benadryl) 25–50 milligrams PO/IV/IM four times a day 5 milligrams/kg/d PO/IV/ IM in four divided doses; maximum dose, 300 milligrams/d Hydroxyzine (multiple trade names) 25–100 milligrams PO three or four times a day 2 milligrams/kg/d PO in four divided doses Cetirizine* (Zyrtec ) 5–10 milligrams PO once a day For children ≥6 y, 5–10 milligrams PO once a day† Fexofenadine* (Allegra) 60 milligrams PO twice a day For children ≥6 y, 30 mil ligrams PO twice a day Loratadine* (Claritin ) 10 milligrams PO once a day For children ≥6 y, 10 mil ligrams PO once a day † Famotidine (Pepcid) 20 milligrams PO twice daily 0.5 milligram/kg/d in two divided doses; maximum dose, 40 milligrams/d Ranitidine (Zantac) 150 milligrams PO twice daily 5–10 milligrams/kg/d PO in two divided doses; maximum dose, 300 milligrams/d *Indication limited to chronic idiopathic urticaria (see package inserts for details). †Pediatric use is recommended only in children ≥6 years old (see package inserts for details). therefore are recommended in combination with histamine-1 antago nists in the more severe allergic reactions. Numerous other antipruritic therapies are recommended, including Domeboro solution (aluminum sulfate diluted 1:10 with water) soaks and oatmeal baths.  ANTIMICROBIAL AGENTS Topical antibacterial agents are used primarily as adjuncts to wound dressing and are rarely useful as primary therapy for superficial bacte rial infections of the skin. The exception to this statement is topical mupirocin, which is as effective as oral antimicrobial agents in the management of impetigo. For wound dressing, the agents commonly used include polymyxin B, bacitracin, neomycin, and silver sulfadiazine. Do not use silver sulfadiazine on the face because it will stain. When reapplying silver sulfadiazine, thoroughly wipe off the prior medication before applying a new dose to avoid silver staining of the skin. Benefits of topical antibacterial agents include reduced adherence of bandaging material to the wound, reduced coagulum, and decreased bacterial colonization. The impact on the rate of wound healing and the prevention of wound infection is less well characterized. Another application of topical antibacterial agents is in the treatment of aphthous stomatitis, for which oral tetracycline rinses are used. Other disorders treated with topical agents include Candida infections, dermatophyte infections, herpes simplex, and lice infestations and scabies. Diagnostic features and specific treatment are discussed in other chapters by the specific diagnosis.  NONANTIMICROBIAL TOPICAL AGENTS In general, the maxim “If it’s dry, wet it, and if it’s wet, dry it” applies to the initial treatment of many rashes. Water, protein, and lipid losses characterize dry skin diseases.

. Diagnostic features and specific treatment are discussed in other chapters by the specific diagnosis.  NONANTIMICROBIAL TOPICAL AGENTS In general, the maxim “If it’s dry, wet it, and if it’s wet, dry it” applies to the initial treatment of many rashes. Water, protein, and lipid losses characterize dry skin diseases. Emollient creams and lotions restore water and lipids to the epidermis, hasten the healing process, and reduce pruritus and pain. Emollients are moisturizers that reduce skin dryness and decrease skin friction and the sensation of tightness. In patients with chronic drying dermatitides, ointments are best, particularly in the winter months. In warm climates, less viscous, less oily preparations, such as a cream, are better tolerated. Open wet dressings using tap water or normal saline not only reduce discomfort due to the drying but also cleanse the skin by painlessly loosening crusts and exudates. The various Tintinalli_Sec20_p1607-1668.indd 1622 8/2/19 7:24 PM