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CHAPTER 252: Skin Disorders: Groin and Skinfolds 1651 FIGURE 251-28. Folliculitis. [Photo contributed by University of North Carolina Department of Dermatology.] FIGURE 251-29. Hot tub folliculitis. [Photo contributed by University of North Carolina Department of Dermatology.] FIGURE 251-30. Kaposi’s  sarcoma. [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.] KAPOSI’S SARCOMA Kaposi’s sarcoma is a vascular neoplasia characterized by endothelial cell proliferation with multisystem involvement. Human herpesvirus 8 has been identified in all variants of the lesions, although it is not known how this virus induces the proliferation of the microvasculature. Individuals infected with human immunodeficiency virus are at high risk for Kaposi’s sarcoma. The use of highly active antiretroviral therapy has reduced the incidence by 10-fold. The clinical presentation of Kaposi’s sarcoma is different from the classic form seen in elderly males of eastern Euro pean heritage. Patients with human immunodeficiency virus can present with widespread, numerous lesions. The lesions may be erythematous or violaceous macules that can progress to tumors or nodules. The lesions on the trunk may be arranged parallel to the skin tension lines and can occur in areas of trauma (Figure 251-30). Erosions, ulceration, crusting, and hyperkeratosis may be secondary changes seen. The trunk is an area of predilection, as are the hard palate, penis, and lower extremities. Classical or European Kaposi’s sarcoma occurs in elderly males of Mediterranean or Ashkenazi Jewish heritage. This variant predomi nantly arises on the lower extremities and can be associated with edema. It can also affect the lymph nodes and abdominal viscera. Treatment depends on the extent and severity of the disease and underlying cause. Referral to infectious disease and hematology/oncology specialists is necessary in most cases. REFERENCES The complete reference list is available online at www.TintinalliEM.com. Skin Disorders: Groin and Skinfolds Alexandra E. Zeitany Diana B. McShane Dean S. Morrell INTRODUCTION The skinfolds of the body include the groin, intergluteal cleft, axilla, inframammary, and pannus regions. Although many skin diseases can affect the skinfolds to some degree, this chapter focuses on the most common skinfold eruptions (Table 252-1). Sexually transmitted infections are discussed in Chapter 153, “Sexually Transmitted Infections” . Molluscum contagiosum is discussed in Chapter 251, “Skin Disorders: Trunk” . The skinfolds have unique characteristics that set them apart from other regions of the body. For one, these areas are almost continuously occluded. As a result, scale does not develop; maceration and fissuring develop instead. This situation alters the appearance of papulosquamous diseases and inflammatory processes. The occlusion also allows for the development of a warm, moist environment favorable to the growth of fungi, yeast, and bacteria. An important point for treatment of intertriginous diseases is avoiding combination corticosteroid and antifungal products. Although processes in the groin folds can be confusing and complicated by secondary change, using combination products may further cloud the clinical picture.

growth of fungi, yeast, and bacteria. An important point for treatment of intertriginous diseases is avoiding combination corticosteroid and antifungal products. Although processes in the groin folds can be confusing and complicated by secondary change, using combination products may further cloud the clinical picture. If improvement is seen after application of combined products, it is difficult to determine which medication prompted the change. Finally, the corticosteroid component of combined medications is too strong to be used in the occluded intertriginous skin and may CHAPTER Tintinalli_Sec20_p1607-1668.indd 1651 8/2/19 7:26 PM

If improvement is seen after application of combined products, it is difficult to determine which medication prompted the change. Finally, the corticosteroid component of combined medications is too strong to be used in the occluded intertriginous skin and may CHAPTER Tintinalli_Sec20_p1607-1668.indd 1651 8/2/19 7:26 PM 1652 SECTION 20: Dermatology TABLE 252-1 Clinical Features and Treatment of Common Disorders of Groin and Skinfolds Condition Clinical Features Treatment Comments Tinea cruris Symmetric, annular, erythematous, scaly plaques Topical antifungals for 1–6 wk Permanent cure is rare, patients require periodic re-treatment Candidiasis Well-demarcated erythema and maceration with satellite pustules involving the skinfolds Topical antifungals; oral fluconazole if recalcitrant and/or recent oral antibiotics Predisposing factors including obesity and endocrine disease such as diabetes or Cushing’s syndrome Scabies Widespread, highly pruritic, erythematous papules; other common locations: intergluteal cleft, digital web spaces, axilla, waistband Look closely for burrows: fine, thread-like lines with a terminal black speck Permethrin cream (safe in pediatric patients older than 2 months) and containment Machine wash and machine dry any clothing, linens, or towels that were worn in 3 days prior to treatment Consider oral ivermectin for immunocompromised patients or refractory cases A negative scabies prep does not rule out this diagnosis; immunocompetent hosts typically harbor less than 20 mites Pediculosis pubis Erythematous macules or papules ± wheals and inguinal lymphadenopathy Look closely for lice and nits Permethrin cream and containment Machine wash and machine dry any clothing, linens, or towels that were worn in 3 days prior to treatment Treat all sexual partners; notify all sexual partners within the past 3 months Approximately 30% of those found to have pediculosis pubis also have concomitant infection with another sexually transmitted infection Seborrheic dermatitis Erythematous plaques with loose greasy scale Antifungal shampoos or creams ± low-potency topical corticosteroid creams (hydrocortisone, desonide) There is no cure, and the condition is expected to wax and wane Intertrigo Erythema/erosions of opposing skin surfaces Conservative measures aimed at eliminating friction, moisture Barrier creams such as Desitin  Diagnosis of exclusion; consider streptococcal infection, Candida, irritant dermatitis May require antifungal treatment as it is often superinfected with Candida Avoid combination antifungal–topical steroid creams as these often contain mid-potency steroids that are too strong for use in intertriginous areas Hidradenitis suppurativa Firm, tender nodules and abscesses often with extensive scarring and sinus tract formation; often also found in axilla, inframammary folds, and under the panus For acute flares: intralesional triamcinolone injections or oral antibiotics (doxycycline or combination therapy with clindamycin and rifampin) Because this is a chronic disease with many social and psychological implications, refer to dermatology and plastic surgery for long-term management FIGURE 252-1. Tinea cruris. Note raised, sharp-edged margins. [Photo contributed by University of North Carolina Department of Dermatology.] produce irreversible striae with long-term use. Chronic use of potent topical corticosteroids should be followed by a dermatologist. 1,2 TINEA CRURIS Tinea cruris is a fungal infection of the groin commonly called jock itch. It is very common in males, uncommon in females, and exceedingly rare in children. Tinea cruris results from invasion of the stratum corneum by the dermatophyte types of fungi (see Table 253-4).

d be followed by a dermatologist. 1,2 TINEA CRURIS Tinea cruris is a fungal infection of the groin commonly called jock itch. It is very common in males, uncommon in females, and exceedingly rare in children. Tinea cruris results from invasion of the stratum corneum by the dermatophyte types of fungi (see Table 253-4). It is transmitted via direct contact (person to person or animal [usually kittens or pup pies] to person) or fomites. Lesions are characterized by symmetric erythema with a periph eral annular slightly scaly edge ( Figure 252-1). The groin is typically involved, and the process may extend onto the inner thighs and even the buttocks. The penis and scrotum are typically spared, a distinguish ing feature of tinea cruris because most other eruptions will affect the scrotum. Frequently, tinea pedis is also present, and the infection may spread from the feet to the groin when putting on clothes. Scraping the leading edge and performing a potassium hydroxide examination will demonstrate branching hyphae, unless the patient has recently applied topical antifungal preparations. Treatment is with antifungal creams, such as clotrimazole, keto conazole, or econazole, twice a day (Table 252-2). Start with clotrimazole because it is low cost and available without a prescription. Econazole also has antibacterial properties and is preferred if maceration is present. Keep the affected area as cool and dry as possible, and recommend loose-fitting clothing. Use an antifungal powder daily to prevent recur rences. Recommend follow-up with a primary care provider or derma tologist if the eruption has not resolved in 4 to 6 weeks. CUTANEOUS CANDIDIASIS Candidal infections of the skin favor moist, occluded areas of the body. Superficial Candida infections are commonly seen in the diaper area of infants, vulva and groin of women, glans penis (balanitis) of Tintinalli_Sec20_p1607-1668.indd 1652 8/2/19 7:26 PM

ption has not resolved in 4 to 6 weeks. CUTANEOUS CANDIDIASIS Candidal infections of the skin favor moist, occluded areas of the body. Superficial Candida infections are commonly seen in the diaper area of infants, vulva and groin of women, glans penis (balanitis) of Tintinalli_Sec20_p1607-1668.indd 1652 8/2/19 7:26 PM CHAPTER 252: Skin Disorders: Groin and Skinfolds 1653 FIGURE 252-2. Cutaneous candidiasis with satellite papules and pustules. [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.] TABLE 252-2 Commonly Used Topical Antifungal Preparations Generic Trade Formulations Status Clotrimazole Lotrimin 1% cream or solution OTC Mycelex 1% solution OTC Ketoconazole Nizoral; Xolegel gel; Kuric gel 2% cream, shampoo, gel Prescription Econazole Spectazole 1% cream Prescription Miconazole Zeasorb AF 2% cream or powder OTC Abbreviation: OTC = over the counter (no prescription required in United States). uncircumcised males, and inframammary and pannus folds of obese patients. Antibiotic therapy, systemic corticosteroid therapy, urinary or fecal incontinence, immunocompromised states, poorly controlled diabetes mellitus, and obesity are predisposing factors. Women with vulvar or inner thigh involvement will often have vaginal candidiasis as well. Frequently, Candida infection may complicate other inflammatory intertriginous disorders. The typical presentation is erythema and maceration with peripheral small erythematous papules or satellite pustules ( Figure 252-2). The rim of satellite pustules helps to distinguish Candida infection from other eruptions of the skinfolds. A potassium hydroxide preparation of the pustules or of the leading edge scale may demonstrate short hyphae and spores, but these may be difficult to find. If Candida is suspected and the diagnosis is in question, obtain a skin swab for fungal culture. Treat with a topical antifungal cream, such as clotrimazole, ketoconazole, or econazole. Keep the affected area dry and cool. Clothing should be loose and lightweight. Astringent solutions (such as aluminum acetate [Burow’s solution]) aid in drying weepy inflam matory eruptions. Once the infection is controlled, recommend daily application of drying powders. Patients with vulvar candidiasis should be evaluated and treated for Candida vaginitis (see Chapter 102, “Vulvovaginitis”). Patients with Candida balanitis often have a female sexual partner with Candida vaginitis, so evaluate and treat partners as well. In infants or adults with urinary or fecal incontinence, change diapers frequently. Zinc oxide paste applied over the antifungal agent provides a protective barrier to the irritation of urine and feces. SCABIES Infestation of the skin by Sarcoptes scabiei, or scabies mite, produces an intensely pruritic eruption. Symptoms manifest approximately 30 days following exposure to the organisms as a result of the host immune response to the mites and their excrement. History may elicit an encounter with another person, or with a new environment, about 4 to 6 weeks before the symptoms appear. Scabies infestation is a major problem in immigrants and asylum seekers, where both prevention and treatment are initiated to control the disease. 3 Individuals with crusted scabies have very large numbers of mites and are quite contagious. Transmission can occur from brief skin or fomite contact. The main presenting feature is intense, intractable pruritus, most notable at night. In adults, the typical findings are slightly longitudi nal erythematous or brown papules, predominantly on the lateral feet, wrists, ankles, and interdigital spaces of the fingers and toes.

can occur from brief skin or fomite contact. The main presenting feature is intense, intractable pruritus, most notable at night. In adults, the typical findings are slightly longitudi nal erythematous or brown papules, predominantly on the lateral feet, wrists, ankles, and interdigital spaces of the fingers and toes. Involvement may be evident within the axillae, groin, and extensor extremities (Figure 252-3). The head and neck are characteristically spared. A variant, crusted or Norwegian scabies, can develop in the immuno compromised, those with dementia, or those who are institutionalized (Figure 253-4). Crusted scabies consists of thick, crusted, confluent plaques on the hands, feet, and scalp, with or without a generalized distribution. Pruritus is not a common feature of crusted scabies. To visualize the organisms by light microscopy, scrape a burrow with a scalpel blade, transfer to a glass slide, and cover with a drop of mineral oil and a coverslip (see Figure 251-15). Sensitivity of this test is limited, and a negative result does not rule out the diagnosis. Treat with 5% permethrin cream (pregnancy category B), apply from the neck down, leave on for 12 hours, and then bathe with soap and water. Repeat treatment in 1 week. Treat all resident family members and household and intimate contacts. Do not prescribe lindane to children or pregnant women second ary to neurotoxicity. Oral ivermectin is an alternative to permethrin cream, but it may have a slightly lower cure rate. 2 It is given as a single oral dose, 150 micrograms/ kg. Oral ivermectin can be used as an adjunct to permethrin for FIGURE 252-3. Scabetic papules and burrows. [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 1653 8/2/19 7:26 PM

ectin can be used as an adjunct to permethrin for FIGURE 252-3. Scabetic papules and burrows. [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 1653 8/2/19 7:26 PM 1654 SECTION 20: Dermatology refractory cases or in the setting of an immunocompromised or uncooperative patient. Do not prescribe ivermectin to pregnant and lactating women or to children weighing less than 15 kg. Supportive care involves use of oral antihistamines and topical cor ticosteroids after use of the appropriate scabicidal agent. Symptoms gradually resolve over 1 to 2 weeks, although pruritus can sometimes persist for several weeks. Return of new lesions after initial improvement signifies incomplete treatment or reinfestation. PEDICULOSIS PUBIS Pediculosis pubis is infestation of the groin with Phthirus pubis. Rarely, the eyebrows, eyelashes, chest, or axillary hair may also be involved. Close examination of the hair-bearing areas reveals multiple, small, flesh-colored or slightly reddish organisms grasping the hairs close to the skin surface (Figure 252-5). In severe infestations, small bluish-gray macules may be noted, called maculae caeruleae. Secondary infection and excoriations may also be present. Diagnosis of pediculosis pubis in children should prompt evaluation for sexual abuse. Treatment is the same as for scabies . Topical treatments should be applied liberally to all affected hair-bearing areas, including the perirectal hairs. SEBORRHEIC DERMATITIS Seborrheic dermatitis is one of the most common skin disorders. It most notably affects the scalp (“dandruff ”) and creases of the face and ears; however, other skinfolds, such as the intergluteal cleft, groin, axilla, inframammary folds, and umbilicus, can be affected (see Chapters 250, “Skin Disorders: Face and Scalp” and 251, “Skin Disorders: Trunk”). It is a chronic condition that typically reappears after stopping treatment. Seborrheic dermatitis of the scalp and skinfolds of the face presents as erythema with a greasy yellow scale (see Figure 250-1). When seborrheic dermatitis affects other skinfolds, erythema and maceration are evident. Diagnosis is clinical. By itself, groin or other skinfold involvement is hard to differentiate from cutaneous candidiasis, inverse psoriasis, allergic contact dermatitis, or streptococcal infection. Treatment is symptomatic. Shampoos containing zinc pyrithione, selenium sulfide, salicylic acid, or tar preparations are used. Ketocon azole shampoo can be effective and is available by prescription (2%) or over the counter (1%). Hydrocortisone 1% cream can be used in mild cases, whereas hydrocortisone 2.5% cream or desonide cream or lotion may be required initially in more severe cases. Avoid long-term regular use of corticosteroids on facial or intertriginous skin, which may result in irreversible skin thinning and striae formation. INTERTRIGO Intertrigo is an irritant dermatitis of the skinfolds resulting from moisture, heat, friction, and irritating substances like urine and feces. Intertrigo presents as erythema, maceration, and fissures in the occluded area of skinfolds, especially the groin and inframammary folds ( Figure 252-6). Satellite papules and pustules are absent , and the affected areas are FIGURE 252-4. Norwegian or crusted scabies. [Reproduced with permission from Knoop KJ, Stack LB, Storrow AB, Thurman RJ (eds): The Atlas of Emergency Medicine , 4th ed. McGraw-Hill Education, Inc., New York, 2016. Fig. 20.35, p. 709. (Photo Contributor: Larry Mellick, MD).] FIGURE 252-5. Arrow points to louse on the skin.

URE 252-4. Norwegian or crusted scabies. [Reproduced with permission from Knoop KJ, Stack LB, Storrow AB, Thurman RJ (eds): The Atlas of Emergency Medicine , 4th ed. McGraw-Hill Education, Inc., New York, 2016. Fig. 20.35, p. 709. (Photo Contributor: Larry Mellick, MD).] FIGURE 252-5. Arrow points to louse on the skin. [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 252-6. Intertrigo with possible streptococcal superinfection. [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 1654 8/2/19 7:26 PM