Random Dermatology MCQ - Impetigo Herpetiformis

A 35-year-old woman presents with recurrent crops of sterile pustules on her palms and soles, along with fever and leukocytosis. She is 32 weeks pregnant. Which of the following is the most likely diagnosis?

A) Impetigo herpetiformis
B) Erythema multiforme
C) Dyshidrotic eczema
D) Scabies
E) Tinea manuum

Correct Answer: A) Impetigo herpetiformis

Explanation

This patient has impetigo herpetiformis, a rare form of pustular psoriasis of pregnancy. Key features include:

• Sterile pustules in annular patterns, typically starting in flexural areas and spreading to trunk/extremities

• Systemic symptoms: fever, malaise, leukocytosis

• Hypocalcemia is common (check calcium levels)

• Occurs most often in the third trimester

Why not the others?

• (B) Erythema multiforme: Targetoid lesions, often triggered by infections/medications

• (C) Dyshidrotic eczema: Pruritic vesicles (not pustules), no systemic symptoms

• (D) Scabies: Burrows, intense nocturnal pruritus, no fever

• (E) Tinea manuum: Unilateral scaling, KOH-positive

Critical management points:

1. High-risk condition - can lead to placental insufficiency/fetal distress

2. First-line treatment: Systemic corticosteroids

3. Delivery may be required for severe cases

4. Monitor for hypocalcemia (may need calcium/vitamin D)

DDx: Other pregnancy-related dermatoses (PEP, PG)