A 6-month-old infant had itchy erythematous papules and exudative lesions on the scalp, face, groins and axillae for one month. She also had vesicular lesions on the palms. The most likely diagnosis is –
**Core Concept**
The infant's symptoms suggest a skin condition characterized by itchy, erythematous papules and exudative lesions, often accompanied by vesicular lesions on the palms, a classic sign of a specific dermatological disorder.
**Why the Correct Answer is Right**
The infant's presentation is consistent with atopic dermatitis (AD), also known as eczema. Atopic dermatitis is a chronic inflammatory skin condition characterized by impaired skin barrier function, leading to increased permeability and susceptibility to allergens, irritants, and infections. The symptoms are exacerbated by dry skin, stress, and environmental factors. The presence of vesicular lesions on the palms, known as dyshidrotic eczema, is a common feature of AD.
**Why Each Wrong Option is Incorrect**
* **Option B:** Contact dermatitis is an allergic or irritant reaction to a specific substance, but it typically presents with localized lesions, unlike the widespread nature of this infant's symptoms.
* **Option C:** Impetigo is a bacterial infection of the skin, often caused by Staphylococcus aureus, which presents with honey-colored crusts and is less likely to involve the palms.
* **Option D:** Psoriasis is a chronic autoimmune condition characterized by scaly, erythematous plaques, but it typically affects the trunk, scalp, and extremities, and is less likely to involve the palms or have a vesicular component.
**Clinical Pearl / High-Yield Fact**
Atopic dermatitis is a classic example of a "pruritus-urticaria-eczema" syndrome, where pruritus (itching) is the primary symptom, followed by urticaria (hives), and finally eczema (dermatitis).
**Correct Answer: A. Atopic dermatitis (eczema).**