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:

Child is showing features of scabies, caused by infestation with Sarcoptes scabiei. It is usually acquired by sleeping with or in the bedding of an infested individual or by other close contact. Clinical Findings: Itching is the most common symptom. Lesions consist of generalized excoriations with small pruritic vesicles, pustules, and burrows in the web spaces and on the heels of the palms, wrists, elbows, around the axillae, and on the breasts of women. Nodular lesions may occur on the scrotum or penis and along the posterior axillary line. Diagnosis is confirmed by microscopic demonstration of the organism, ova, or feces in a mounted specimen examined with tap water. Ref: Current Medical Diagnosis and Treatment, 2012, Chapter 6; Harrison's Principles of Internal Medicine, 18th Edition, Chapter 169.