This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
A female has hypopigmented lesions in the centre of the forehead. Drug responsible is? 
Select and explain. 
A. Hydroquinone, B. Ether metabolite of hydroquinone, C. Para tertiary butyl catechol, D. Para tertiary butyl phenol
D: Para tertiary butyl phenol
Answer: D: Para tertiary butyl phenol 
Explanation: This is a characteristic chemical leukoderma caused by the use of bindi due to its characteristic location (centre of forehead).
Para tertiary butylphenol (PTBP) is present in the adhesives of the bindi and result in leukoderma.

REMEMBER: Most potent agent causing chemical leukoderma is Monobenzyl ether of hydroquinone.