Chapter 155. Other Dermatologic Disorders

Acne fulminans is a severe form of cystic acne with ulcerating lesions associated with systemic symptoms such as fever, myalgias, arthralgias, and hepatosplenomegaly. Pyoderma faciale is an inflammatory cystic acneiform eruption on the central face of young women. Severe scarring can result without treatment. Dissecting cellulitis of the scalp and neck is an inflammatory scarring process seen mostly in young black males. Acne keloidalis nuchae is a perifollicular inflammatory process of the scalp. These diagnoses are made clinically.

Acute treatment of acne fulminans and pyoderma faciale includes systemic corticosteroids (prednisone 40 to 60 milligrams daily) and continuation of isotretinoin if already on it. Dissecting cellulitis of the scalp is treated with 5% to 10% benzoyl peroxide washes and oral doxycycline or minocycline. Acne keloidalis nuchae can be treated with topical clindamycin, topical corticosteroids (fluocinonide), and oral doxycycline or minocycline. Refer to a dermatologist for further management, including consideration of initiation of isotretinoin.

Herpes zoster results from activation of latent varicella zoster virus.

Clinical Features

Pain or dysesthesia in the involved dermatome begins several days before lesions emerge. Erythematous papules develop first, progress to vesicular clusters, which crust after about a week. Lesions of the ophthalmic branch of the trigeminal nerve, especially if accompanied by lesions on the nose, are concerning for ophthalmic involvement (keratitis, ulceration) (Fig. 155-1). A thorough eye exam, including slit lamp exam, should be performed (see Chapter 149 “Ocular Emergencies”). Generalized eruptions may occur in immunocompromised patients.

Diagnosis and Differential

The differential diagnosis includes herpes simplex, impetigo, and contact dermatitis. The key to diagnosis in patients is pronounced pain at the site and a unilateral distribution. A Tzanck prep and viral PCR can confirm the clinical diagnosis.

Emergency Department Care and Disposition

1. Antivirals started in the first 72 hours of presentation shortens healing time, decreases formation of new lesions, and helps prevent postherapeutic neuralgia. Antiviral choices include acyclovir 800 milligrams PO 5 times per day for 7 to 10 days or valacyclovir 1000 milligrams PO three times a day for 7 days. Patient with HIV/AIDS should take acyclovir for 21 days.

2. Aluminum acetate compressions three times daily and analgesics provide symptomatic relief.

3. Advise patients that herpes zoster is contagious to anyone who has not had chicken pox or the varicella zoster vaccine.

4. Consult with an ophthalmologist if eye involvement is suspected.

Herpes simplex virus (HSV) lesions are painful grouped vesicles with an erythematous base. Primary disease may be preceded with or accompanied by constitutional symptoms. Tingling or burning precedes recurrent lesions. Oral lesions (“cold sores”) are usually caused by HSV1, but may be caused by HSV2. The diagnosis can be confirmed with a Tzanck preparation and HSV PCR test if necessary. Treatment (Table 155-1) is best if started within 24 hours of symptom onset. See Chapter 87 “Sexually Transmitted Diseases” for discussion and treatment of genital herpes.

Tinea refers to skin infections caused by dermatophytes (fungi).

Clinical Features

Tinea capitis is characterized by patchy areas of alopecia with broken off hairs and scales at the periphery. Tinea barbae presents with severe inflammatory plaques and follicular pustules in the beard area. Interdigital scaling, maceration, plantar or palmar erythema or scaling, and pruritis are seen in Tinea pedis (feet, also known as athlete's foot) and Tinea manuum (hand). Onchomycosis may occur. Findings in Tinea cruris (groin, commonly called jock itch) include erythema with a peripheral annular scaly edge that extends onto the thighs and buttocks but spares the penis and scrotum. Candida intertrigo involves the skinfolds. Tinea Corporus (trunk, neck, arms, and legs lesions) are typically circular, covered with scales and surrounded by a raised border.

Diagnosis and Differential

Identification of fungal elements on a potassium hydroxide preparation or with fungal culture may be required if the diagnosis is uncertain. The differential diagnosis includes psoriasis, atopic, seborrheic, and chronic dermatitis (Table 155-2).

Emergency Department Care and Disposition

1. Treat Tinea capitis and barbae with oral ultramicrosized griseofulvin 500 milligrams PO daily (children: 20 to 25 milligrams/kilogram/d) for 6 to 8 weeks, terbinafine 250 milligrams PO daily (children > 4 years of age, 125 milligrams daily) for 6 to 8 weeks, or itraconazole 200 milligrams daily (children 3 to 4 milligrams/kilogram/d) for 2 to 4 weeks. Consider baseline liver function tests. Initiation of oral antifungal treatment in patients with altered hepatic function is not recommended. Advise patients to wash hair with selenium sulfide 2.5% shampoo or ketoconazole 2% shampoo three times per week for 2 weeks.

2. Treat nonbullous tinea pedis and manuum, intertrigo, tinea corpora, tinea cruris, with topical antifungal agents such as clotrimazole, miconazole, ketoconazole, or ciclopirox twice daily for 2 to 4 weeks. Continue treatment 1 week after clearing has occurred. Antifungal powders used on a daily basis help prevent recurrences of tinea cruris.

3. Onchomycosis usually requires long term oral treatment.

4. Follow-up with a primary care physician or dermatologist is recommended, especially if the lesions are not resolved in 4 to 6 weeks.

See Chapter 120 Bites and Stings for discussion of diagnosis and treatment of scabies and lice.

Clinical Features

Contact dermatitis occurs after direct contact with an irritant or allergen. Reactions occasionally occur after exposure to aerosolized particles, such as burned poison ivy or oak. Detergents and soaps are common irritants; nickel, plants, cosmetic preservatives, contact lens solutions, and skin tape are common allergens. Physical findings include erythema, papules, vesicles and bullae. Scaling and fissuring are seen with chronic contact dermatitis.

Diagnosis and Differential

The differential diagnosis includes dyshidrotic eczema, atopic dermatitis, and fungal infections.

Emergency Department Care and Disposition

1. Treatment begins with removing the offending agent.

2. Aluminum acetate or normal saline compresses two or three times per day help ease acute irritation.

3. Oral antihistamines, such as hydroxyzine 25 to 50 milligrams PO 4 times a day, relieve pruritus.

4. Topical corticosteroids applied twice or thrice daily will reduce inflammation. The potency of the topical corticosteroid used is dependent on the severity of the reaction. Only low potency topical corticosteroids, such as hydrocortisone 2.5%, should be used on the face.

5. Patients with extensive severe allergic contact dermatitis may require a burst of systemic corticosteroids followed by a taper.

Patients with sunburn have an inflammatory response to ultraviolet (UV) radiation and may present with minimal discomfort or extreme pain with extensive blistering. A tender, warm erythema is seen in sun-exposed areas; vesiculation may occur, representing a second-degree burn. Exogenous photosensitivity results from the topical application or ingestion of an agent that increases the skin's sensitivity when exposed to UV light. Topically applied furocoumarins (lime juice, various fragrances, figs, celery, parsnips), PABA esters (sunscreen), and topical psoralens can cause photosensitivity at the site of application. Numerous medications, including sulfonamides, thiazides, furosemide fluoroquinolones, tetracyclines, cause photosensitivity eruptions which involves all sun-exposed areas. The exogenous photoeruption looks similar to a severe sunburn reaction, often with blistering.

Sunburn should be suspected in a patient with significant outdoor UV light exposure. The diagnosis of exogenous photosensitivity is based on identifying the offending agent. A linear rash appearance suggests an externally applied substance. Sunburns are treated symptomatically with tepid baths, NSAIDs, and wound care including topical antibiotics to blistered areas. Initial management of exogenous photosensitivity is similar to the sunburn reaction, including the avoidance of the sun until the eruption has cleared. Discontinue the causative agent, if possible.

Psoriasis is a chronic skin disorder characterized by symmetric discrete erythematous plaques with a silver scale typically located on the extensor surfaces (knees, elbows), scalp and chest. β-blockers, lithium, and antimalarials may exacerbate the condition. Guttate psoriasis presents more acutely with scattered discrete lesions sometimes following an infection such as streptococcal pharyngitis. Pustular psoriasis presents with scaling and numerous painful pustules on the palms and soles. The differential diagnosis of psoriasis can be found in Table 155-2. The diagnosis of psoriasis is usually made clinically but a biopsy may be required. Treatment is initiated in consultation with a dermatologist. Topical treatments for localized plaques include moisturizers, topical corticosteroids, tar and vitamin D preparations. Antibiotics are indicated for streptococcal infections. Patients with diffuse pustular psoriasis often require admission for hydration and supportive care.