Leprosy: type 1 (reversal) leprosy reaction

Borderline tuberculoid (BT) leprosy: type 1 (reversal) leprosy reaction This is a medium power view of a skin section from a patient with BT. Beneath the epidermis the granuloma is diffuse, rather than compact. Note also that there is oedema in the dermis (seen as 'white spaces' that contain fluid). H&E stain. This represents a mild type 1(reversal) reaction, with oedema as the main feature.