This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vesiculobullous (Blistering) Disorders, Subject name: Skin
A30-year-old male had severely itchy popular vesicular lesions on extremities knee, elbows and buttocks for one year. Direct immunofluorescence staining of the lesions showed IgA deposition at dermo epidermal junction. The most probable diagnosis is: 
Select and explain. 
A. Dermatitis herpetiform, B. Pemphigus vulgaris, C. Nummular eczema, D. Bullous pemphigoid
A: Dermatitis herpetiform
Answer: A: Dermatitis herpetiform 
Explanation: Ans. a. Dermatitis herpetiformDermatitis herpetiformis is also known as duhring -Brocq disease