What's the cause of these annual bumps?
Case 1:
For the past few years, itchy red bumps have appeared on a 59-year-old man’s trunk during the winter; the lesions slowly resolve as the weather warms. The patient does not use moisturizer or hot tubs and has not changed his brand of soap, detergent, or fabric softener in many years.
What condition is responsible for these lesions?
A. Bacterial folliculitis.
B. Yeast folliculitis.
C. Grover disease.
D. Psoriasis.
E. Asteatotic eczema.
Case 1 Answer: A biopsy confirmed the clinical impression of Grover disease, C, which can be transient or persistent. The disorder most frequently occurs on the trunk of middle-aged men; it typically presents as highly pruritic, erythematous papules that may be keratotic, but not folliculocentric. The cause is unknown. There is some anecdotal evidence that the disease worsens in winter.
Bacterial and fungal folliculitis involve hair follicles. Generally, psoriasis features flatter, more scaly papules and plaques. The lesions of asteatotic eczema, which arise on the extremities as well, are also flatter and more scaly.
Case 2:
A 28-year-old woman presents with pruritic, tender plaques on her elbows and hands. The lesions first appeared after she began taking an oral contraceptive 4 months ago. The patient is otherwise healthy and uses no other medications.
You suspect which of the following?
A. Psoriasis.
B. Dermatitis herpetiformis.
C. Contact dermatitis.
D. Urticaria.
E. Erythema multiforme.
Case 2 Answer: A biopsy of a lesion confirmed the diagnosis of erythema multiforme, E, a reactive process that can be caused by infection or medication. The patient elected to stop taking the oral contraceptive, and the rash disappeared.
Case 3:
For the past 2 to 3 weeks, pruritic papules have gradually arisen on a 33-year-old African American man’s trunk and proximal extremities. The patient is otherwise healthy and takes no medications.
Which of the conditions in the differential is the likely diagnosis?
A. Contact dermatitis.
B. Pityriasis rosea.
C. Syphilis.
D. Folliculitis.
E. Chickenpox.
Case 3 Answer: On black skin, pityriasis rosea, B, can present as a papular eruption; this common variant may be confused with syphilis, which needs to be ruled out. Pityriasis rosea is of uncertain origin and is self-limited; the eruption resolves without a trace in up to 6 weeks.
Chickenpox usually has a more acute onset and a more vesicular rash, which lasts about 1 week. Unlike this patient’s eruption, folliculitis is centered around a hair follicle. Contact dermatitis usually does not present with discrete papules in this distribution.
Case 4:
A 34-year-old man has had a progressive, red, pruritic rash primarily on his trunk for several weeks. The rash erupted about 2 to 3 weeks after he had a mild upper respiratory tract illness. The patient takes
no medications.
What are you looking at here?
A. Folliculitis.
B. Syphilis.
C. Pityriasis rosea.
D. Guttate psoriasis.
E. Seborrheic dermatitis.
Case 4 Answer: This patient’s erythematous, oval, salmon-colored macules are typical of pityriasis rosea, C. Because this eruption can resemble the rash of second ary syphilis, a VDRL test is warranted in sexually active patients.
Guttate psoriasis can appear after a streptococcal upper respiratory tract infection, but the characteristic lesions are smaller, scalier erythematous plaques that are more evenly distributed over the body. Seborrhea is confined to the mid-chest region. Folliculitis resembles acne.