Dermatology

Hidradenitis suppurativa is a chronic acneiform infection of the cutaneous apocrine glands.

Within the past 7 years, the incidence of methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile infections has significantly increased. Risk factors for MRSA infection include previous antibiotic therapy and living arrangements such as prisons or military barracks that involve close, frequent contact with infected persons. Treat stable patients with MRSA skin infections with oral antibiotics in addition to incision and drainage; hospitalization and intravenous antibiotics are recommended for patients whose condition is unstable or who are unlikely to adhere to an oral regimen. A new strain of C difficile, BI/NAP1, has been associated with recurrent infection; more severe disease that mandates urgent colectomy; and dramatically higher mortality in vulnerable populations, such as older adults. Although oral metronidazole has been the mainstay of treatment of C difficile infection, oral vancomycin may be slightly more effective in patients with severe disease.

For the past month, a 67-year-old woman has had a pruritic rash under her left breast. She takes an antihypertensive and is otherwise healthy.

An 89-year-old man reported that this lesion began developing on his left forearm 11 days earlier. It is a keratoacanthoma, a rapidly growing but benign neoplasm that occurs predominantly on the extensor surfaces of the hands and forearms of white men over age 50.

For more than 3 years, a 63-year-old man with a long history of parapsoriasis had multiple hyperpigmented, erythematous plaqueswith scaling on the abdomen, back, feet, and arms. Some lesions had a hypopigmented center. The patient denied systemic symptoms.

This 8-year-old boy's mother thought her son had a fungal infection on his feet. Examination disclosed malodorous, nontender plaque formation on the weight-bearing surfaces of both feet. Within the plaques were round pits and furrows.

Dermclinic

A 52-year-old man presented with asymptomatic papules on his scrotum. The lesions had first appeared 1 year earlier. He had not sustained local trauma to the scrotum, and his medical history was unremarkable. There was no family history of similar skin lesions.

A number of factors heighten the risk of parasitic infections in elderly persons, who often live in communal settings (eg, nursing homes), where they are more likely to encounter parasites, such as the scabies mite.

Dermclinic

An 83-year-old man with a history of hypertension, hyperlipidemia, and diverticulosis was hospitalized because of painless hematochezia of 1 day's duration. Two years earlier, he had undergone surgical excision of a superficial spreading melanoma on his right thigh.

The left middle finger of this 30-year-old man was lacerated in a motorcycle accident. After it was surgically repaired, the finger developed some dystrophy as well as a small, separate fingernail in the lateral sulcus of the proximal nail fold.

For several months, a 55-year-old white construction worker experienced intense burning of the skin when exposed to direct sunlight. In addition, multiple fragile blisters appeared on the dorsa of his hands and arms; these rapidly developed into crusted, superficial erosions.

In Dr David Kaplan's Dermclinic case of a keratoacanthoma in a 63-year-old woman (CONSULTANT, April 15, 2007, page 473), the lesion is referred to as a "low-grade squamous cell carcinoma." However, keratoacanthomas, while previously considered to be a variant of squamous cell carcinoma, are actually benign.

A 39-year-old woman complained of excruciating pain that radiated from a chronic lesion on the left upper lip to the entire left side of the face. She had AIDS but was not receiving antiretroviral therapy.

Dermclinic: A Photo Quiz to Hone Dermatologic Skills

Tuberculin-type hypersensitivity is characterized by marked spongiotic dermatitis with intraepidermal and subepidermal vesiculation and scattered eosinophils.

Your Observations About the Man With the Tripod Sign

This 33-year-old Guatemalan man presented to a medical mission camp with generalized bilateral knee pain and inability to extend his leg without pain. The 4-ft 11-in patient had mild scoliosis, increased elbow carrying angles, and hypoplastic patellae. He had had dysplasia of the nails with triangular lunulae since birth. The fingernails were absent on the first and second digits of both hands. His mother had had similar physical findings. He had not had regular medical care.

A 60-year-old African American woman presented with an asymptomatic, nonpruritic lesion on the left temporal scalp that bled intermittently. She had noticed the lesion after she used a hair relaxant 5 to 6 months earlier. Since then, the lesion had slowly enlarged. She had a history of type 2 diabetes mellitus and hypertension. She denied alcohol consumption and tobacco use.

The sudden appearance of a pruritic confluent erythematous rash on the anterior neck and upper back prompted a 30-year-old woman to seek medical attention. She had recently started applying 5% tea tree oil to the area to treat chronic, recurrent tinea versicolor. An herbal specialist had recommended this therapy.

An 82-year-old man is seen for annual physical examination in the nursing home. He has resided there for 1 year because of the aggregate impact of multiple medical problems including, most prominently, laryngeal swallowing dysfunction associated with vocal cord paralysis.

Tinea corporis appears as an annular plaque with a rim of scaly erythema.

Tinea that occurs on the hands is referred to as tinea manuum.

Maceration or scale between isolated web spaces of the fingers suggests erosio interdigitalis blastomycetica (interdigital candidiasis). It most often occurs in the web space between the middle and ring fingers; sometimes the toes are affected. Erosio can spread and can be painful.

A fungal folliculitis (Majocchi granulomas) can occur if a superficial fungal infection is treated with topical corticosteroids. Fungal folliculitis is best treated with a short course of oral itraconazole or fluconazole.

Candidal infection can also occur at the lateral angles of the mouth; it causes erosions and breakdown of the skin. Angular cheilitis, or perleche, resembles the relationship between intertriginous candidiasis and intertrigo in that it is part infection and part inflammatory response to the impairment of epidermal integrity.

Tinea that occurs on the hands is referred to as tinea manuum. For unknown reasons, tinea often affects two feet and one hand. Tinea manuum must be distinguished from allergic contact dermatitis of the hands, which it resembles; this can be done by examination of a potassium hydroxide preparation. Tinea manuum can be treated with a topical antifungal agent.

This infection is usually caused by Candida albicans, whichis often present in body folds. Candidiasis is common in persons with diabetes and in obese persons. Other predisposing factors are the use of antibiotics, topical corticosteroids, or immunosuppressive drugs; poor nutrition; and immunosuppression.

Tinea pedis, or athlete's foot, is common in elderly persons. It manifests as maceration in the interdigital web folds and as scaly plaques on the plantar surfaces of the feet. A potassium hydroxide evaluation can establish the diagnosis. Tinea pedis is commonly associated with xerosis. It is best treated with a topical antifungal agent; treatment can be aided by a keratolytic such as lactic acid 12% cream.