October 7th 2025
Psoriasis, lichen planus, and pityriasis rosea share overlapping presentations and comorbidities, but distinct pathophysiologies require accurate diagnosis and tailored therapeutic approaches.
Perifolliculitis Abscedens Et Suffodiens
November 2nd 2008For about 10 years, a 26-year-old man had recurring cystic lesions on his scalp that would periodically enlarge, shrink, and occasionally drain. One lesion had been excised by another physician, but it later recurred. The patient had been taking minocycline (100 mg) daily for this condition.
Regional Folliculitis After Smallpox Vaccination
October 1st 2008For a week, a 36-year-old Marine had clusters of localized papular lesions on the right forearm; he had no systemic symptoms. The patient had been inoculated 20 days earlier in the United States with the vaccinia virus (smallpox vaccine) to the ipsilateral shoulder just before deployment. He had no history of eczema, psoriasis, or drug allergies.
Actinic Cheilitis in a 53-Year-Old Man
October 1st 2008This finely papular, slightly raised lesion below the vermilion border of a 53-year-old man’s lip had been present for several months; it was asymptomatic. Six years earlier, the patient had a squamous cell carcinoma of the left lower leg excised. He worked outdoors on an offshore oil rig.
Violent Purple-Red Thigh Rash in an Aged Woman
August 1st 2008This pruritic rash appears to be a drug reaction to a cephalosporin. This class of drug often produces allergic reactions in the skin; this was quite an ordinary one, neither vasculitic nor urticarial. The mucosa was not affected, which ruled out Stevens-Johnson syndrome.
High-Grade Ductal Carcinoma In Situ
June 2nd 2008For 6 weeks, a 68-year-old woman had had sharp pain in the left breast that radiated to the left arm and back. The pain was worse on palpation; ibuprofen provided only mild relief. She denied nipple discharge, skin discoloration, and fever. She had no family history of breast cancer. Results of a biopsy of the left breast 6 years earlier were benign. Her most recent mammogram, 4 weeks earlier, was negative.
Congenital Nevomelanocytic Nevus
May 2nd 2008This darkly pigmented lesion on the left arm of a 27-year-old man had been present since birth and had slowly enlarged over the past 2 months. Two days earlier, another physician had diagnosed a wart and treated the lesion with liquid nitrogen, which caused erythema of the surrounding skin.
Differentiating the Types of Tinea
May 1st 2008Tinea is caused by dermatophytes that can infect the stratum corneum epidermidis, hair, and nails. Dermatophytosis is a common infection worldwide, and about 20% of the US population is infected.1 Although numerous fungi can cause tinea, Trichophyton, Microsporum, and Epidermophyton are the genera that cause most cases of tinea.2 Classified by the part of the anatomy that is infected, tinea is referred to as tinea pedis, tinea manuum, tinea cruris, tinea corporis, tinea capitis, tinea faciei, tinea barbae, and tinea unguium.
Asteatotic Eczema on Legs and Steroid Rosacea on Face
April 16th 2008For several years, a 71-year-old man has had a mildly pruritic rash on his legs that develops every winter and resolves when the weather becomes warmer. He is scheduled to undergo knee surgery, but the surgeon refuses to perform the operation until the rash has cleared.
Second-Degree Burn From Iontophoresis
April 16th 2008Half way through a 15-minute iontophoresis treatment for de Quervain tenosynovitis of the right wrist, a 42-year-old woman felt exquisite pain but completed the session. After the therapist returned to the room and removed the electrodes, a light gray circular mark about 5 mm in diameter was noted on the skin. The epidermis was gone, and the underlying dermis was also injured. Within 6 hours, a tender, dark red-brown lesion developed.
Silver Nitrate Staining of Fingernails
April 2nd 2008Black discoloration appeared on the fingernails of a 51-year-old white man who had sustained burns on 15% of his body in a house fire 2 months earlier. The discoloration is a typical side effect of silver nitrate, which was applied to his skin and fingernails during the month he was hospitalized. This topical broad-spectrum bacteriostatic agent is used to reduce the risk of infection and mortality in burn patients.