A 6 month old infant had itchy erythematous papule and exudative lesions on the scalp, face, groins and axillae for one month. She also had vesicular lesion on the palms. The most likely diagnosis is -

<p>As per the features- itchy erythematous papules and involvement of axilla,groin and scalp points to infantile scabies. SCABIES:- Caused by Sarcoptes scabiei var hominis.Clinical features: Itching- generalised, worse at night.this is due to delayed type 4 hypersensitivity reaction. Classic lesion: Burrow-Thread like wavy tunnel in stratum corneum.They appear as serpiginous or S shaped greyish,thread like elevations with a vesicle at one end indicating the presence of mite.seen at interdigital web, feet areola,scrotum. infantile scabies is characterised by - vesicular lesions and pustular lesions - lesions over face scalp, Palms and soles Seborrheic dermatitis:-Dry scaly lesions or greasy scaling over an inflamed lesions.Eye lashes-squamous Blepharitis Truncal lesions-annular/geographical plaques or erythematous patches(petaloid lesions) with peripheral scaling (pityriasiform lesions) psoriasis:- Inflammatory skin disease.Genetic predisposition. Psoriasis susceptibility 1 (PSORS1) is the most impoant susceptibility locus. Clinical features:-1. Classic lesion-Well defined erythematous plaque with a silvery white scales.2. Size varies from pin point papules to plaques. {Reference: IADVL textbook of dermatology, page 429