Image shows large U/L hypopigmented lesion on right trunk and arm in young female: segmental vitiligo. Vitiligo Segmental Non segmental Unilateral along dermatome Localised Generalised Focal: few mucosal: mucosa -Vulgaris - MC, B/L symptoms - Acrofacial (including hand and face) - Universalis >90% Etio: Autoimmune condition - Antibody formed destroy melanocytes Neurogenic hypothesis - It is only valid for segmental type The image shown above in question is of Segmental vitiligo Self-destruct theory of Lerner - Given for vitiligo It states that the oxidative stress which is going on in body causes destruction of melanocytes. If question would be about Vitiligo or B/L type, answer would be Autoimmune hypothesis. If there is family history of Vitiligo , answer would be Genetic factors