A young boy presented with lesion over his right buttock which had peripheral scaling and central scarring. The investigation of choice would be –

The boy is having lupus vulgaris because the lesions have central scarring. Central Scarring is a feature of lupus vulgaris. Diagnosis of lupus vulgaris is confirmed by Biopsy. Remember  Feature                                                                     Central clearing                                         Central Scarring                                      Central Crusting                                       Disease Tinea corporis    Lupus Vulgaris   Leishmaniasis     Investigation KOH Smear Biopsy LD body demonstration