Extermely pruritic excoriation & papules on buttocks with autoantibodies against epidermal transglutaminase and IgA deposition in dermis on immuno-histological examination of normal perilesional skin. Diagnosis is:
D i.e. Dermatitis herpetiformis
Pemphigus vulgaris
Pemphigoid
Linear IgA disease
Dermatitis herpetiformis