A 7-year-old child presents today with a rash shown below.

He recovered from a recent illness in which he was treated with amoxicillin. Additionally, he had received a Covid-19 vaccination about 1 month ago. Which of the following answer choices best fits this patient?

Answer choices:

A. Guttate psoriasis 

B. Pityriasis rosea

C. Pityriasis lichenoides et varioliformis acuta 

D. Lichen planus

Rationale:

The clinical photograph above shows a child with multiple pink-red papules some with central ulcer and crust consistent with a diagnosis of pityriasis lichenoides et varioliformis (PLEVA). 

Correct answer: C. Pityriasis lichenoides et varioliformis acuta (PLEVA)

PLEVA is a T-cell lymphoproliferative disorder that is self-limited typically lasting 1-3 years. It is thought to occur as an immune response to infection, vaccination, or medication. 

A. Guttate psoriasis typically presents as scaly red well demarcated small papules and plaques and can occur postinfectious, commonly after streptococcal infections. It does not typically ulcerate. 

B. Pityriasis rosea is a self-limited eruption starting with a larger plaque with central clearing followed by multiple oval-shaped pink scaly papules and thin plaques along skin cleavage lines. 

D. Lichen planus typically appears as flat-topped purple pruritic papules with white streaks commonly occurring on the wrists, ankles, and shins. Widespread distribution can also occur and is more common in drug-induced lichen planus. 

Additional reading at Weinberg's Color Atlas of Pediatric Dermatology Section 12: Papulosquamous Diseases.