Dermclinic: A Photo Quiz to Hone Dermatologic Skills

Case 1:

A 19-year-old man has been bothered for several weeks by a pruritic rash on the forearms and hands. He has never had a similar outbreak. The rash erupted shortly after he started work as a short-order cook. He has a history of seasonal allergies.

What does this look like to you?

A. Tinea corporis.

B. Pityriasis rosea.

C. Nummular eczema.

D. Asteatotic eczema.

E. Irritant dermatitis.

F. Lichen simplex chronicus.

Case 1: The patient has a combination of nummular eczema (seen inclose-up view), asteatotic eczema, and irritant dermatitis, C, D, and E. The outbreak resulted from exposure to the cooking oils that aerosolized off the grill and from the hot water and harsh soaps he used to remove the grease. The patient's atopic tendency made his skin susceptible to irritants and asteatosis. His condition improved after he changed his scrubbing habits, used a milder soap, wore protective clothing to keep the grease off, and applied a topical corticosteroid cream.

Tinea corporis would not present with a sudden eruption of numerous lesions on the forearms. Pityriasis rosea is generally localized to the trunk. Lichen simplex chronicus usually does not manifest as groupings of nummular patches but as a chronic eczematous inflammation.

Case 2:

Pruritic eruptions, primarily on the trunk, have concerned a 56-year-old woman for several weeks. She has not changed her soap or started any new medications. She says she has been under stress recently because of the death of her mother.

Which condition is responsible for the patient's symptoms?

A. Tinea corporis.

B. Pityriasis rosea.

C. Scabies.

D. Asteatotic eczema.

E. Lichen simplex chronicus.

F. Contact dermatitis.

Case 2: This patient has lichen simplex chronicus, E, a neurodermatitis caused by habitual scratching of a localized area. The disorder is precipitated by stress or anxiety and can persist for years. Topical treatment with corticosteroid creams is often only palliative, and the condition quickly relapses. Psychotherapeutic intervention, with or without medication, to address the underlying mood disorder usually succeeds in breaking the itch/scratch cycle.

Tinea can be ruled out by negative results on a potassium hydroxide evaluation. Pityriasis generally presents with a herald patch and discrete oval-shaped macules. Scabies more commonly affects the extremities, especially the wrists and finger webs, which were not involved here. Asteatotic eczema would respond to a change in bathing habits and the use of moisturizers. Contact dermatitis is less likely to be patchy, and the patient had no history of exposure to contactants.

Case 3:

For several months, a 42-year-old man has had a pruritic rash on his back. He has not used a new soap or started any new medications. He has a history of childhood seasonal allergies.

What does this look like to you?

A. Tinea corporis.

B. Pityriasis rosea.

C. Nummular eczema.

D. Asteatotic eczema.

E. Lichen simplex chronicus.

F. Contact dermatitis.

Case 3: The patient has asteatotic eczema, D, a drycondition that can also be scaly and that preferentially affects atopic persons. The condition was exacerbated by long, hot showers during which the patient let the water run on his back and thus strip off protective oils. He was instructed to face the shower; take shorter, cooler showers; and apply moisturizers.

Tinea corporis was ruled out by negative results on a potassium hydroxide evaluation. Pityriasis rosea typically presents with a single herald patch; within 1 to 2 weeks a number of smaller lesions appear, generally on the front of the trunk. Nummular eczema manifests as a more discrete circular patch. Lichen simplex chronicus involves areas that are easy for a patient to scratch. The patient had no history of exposure to contactants, and contact dermatitis would generally not persist for months.

Case 4:

For several weeks, a 6-year-old girl has had a worsening mildly pruritic rash on the trunk. She has a history of seasonal allergies. The family has had a cat and a dog in the house for a number of years.

What do you suspect?

A. Tinea corporis.

B. Pityriasis rosea.

C. Nummular eczema.

D. Asteatotic eczema.

E. Lichen simplex chronicus.

F. Contact dermatitis.