Dermatology MCQ - Viral Infections - Eruptive Pseudoangiomatosis

A 4-year-old child presents with the sudden appearance of dozens of 1-2 mm, bright red, blanching papules on the face and trunk. The child is afebrile and in no distress. The lesions appeared within the past 24 hours. The mother reports the child had a runny nose and cough one week ago. Which of the following is the most likely diagnosis and its typical natural history?

A) Eruptive pseudoangiomatosis; spontaneous resolution within 1-2 weeks
B) Gianotti-Crosti syndrome; persistence for several weeks with associated hepatitis
C) Molluscum contagiosum; persistence for months with potential for autoinoculation
D) Papular urticaria; recurrent episodes triggered by insect bites
E) Cherry angiomas; permanent lesions that increase with age

Correct Answer: A) Eruptive pseudoangiomatosis; spontaneous resolution within 1-2 weeks

Explanation

This presentation is classic for eruptive pseudoangiomatosis (EPA), a benign, self-limiting exanthem of childhood.

Key Clinical Features of Eruptive Pseudoangiomatosis:

• Morphology: 1-4 mm, bright red, blanching papules that resemble small angiomas. Each lesion may be surrounded by a pale halo.

• Distribution: Primarily on the face, trunk, and limbs.

• Onset: Sudden eruption over 24-48 hours.

• Symptoms: The child is typically afebrile and asymptomatic. The lesions are non-pruritic and non-tender.

• Preceding Illness: Often follows a viral upper respiratory infection (e.g., adenovirus, echovirus) or insect exposure.

• Diascopy: Lesions blanch completely with pressure, confirming their vascular nature.

Natural History:

• Spontaneous resolution within 5-10 days without scarring or sequelae.

• Recurrence is uncommon.

Why Not the Other Options?

• (B) Gianotti-Crosti syndrome: Presents with symmetric, flat-topped, flesh-colored or erythematous papules on the face, extremities, and buttocks. The rash persists for 2-8 weeks and is associated with hepatitis (hepatomegaly, elevated transaminases).

• (C) Molluscum contagiosum: Features discrete, pearly, umbilicated papules that persist for months to years and can spread by autoinoculation. They are not bright red or blanching.

• (D) Papular urticaria: Presents as pruritic papules (often with central puncta) in groups, triggered by insect bites. Lesions recur seasonally and last for days to weeks.

• (E) Cherry angiomas: These are permanent vascular lesions that increase in number with age and are common in adults, not young children. They do not erupt suddenly.

Management:

• Reassurance and education about the benign, self-limited course.

• No treatment is necessary.

Prognosis:
Excellent; complete resolution is expected.

Note: EPA is a clinical diagnosis. The sudden onset of blanching red papules in a well child with a recent viral history is pathognomonic. It is important to distinguish it from more serious conditions like meningococcemia (where the child is febrile and toxic with non-blanching purpura) or true angiomas (which are persistent).