This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autoimmune skin disorders, Subject name: Dental
Sexually active male comes with complaints of recurrent ulcers over the glans which heals with hyperpigmentation, probable diagnosis is - 
Select and explain. 
A. Aphathous ulcer, B. Fixed drug eruption, C. Herpes genitalis, D. Chlamydial infection
B: Fixed drug eruption
Answer: B: Fixed drug eruption 
Explanation: Fixed drug eruption manifests as skin lesions at fixed sites following drug intake. The lesions progressively fade over several days often leaving a residual post inflammatory brown pigmentation. Page no.294. Reference IADVL's concise textbook of dermatology