Hypopigmented face patches; their distribution and relevance to ocular complications in leprosy

Eighty-two leprosy patients with hypopigmented patches over the face (cases) and an equal number of age-, sex-, and classification-matched leprosy patients without any hypopigmented patches over the face (controls) were examined for the distribution of hypopigmented facial patches, areas of anesthesia over the face, and eye complications. The hypopigmented patches did not follow any pattern and overlapped in the areas of sensation supplied by the three branches of the trigeminal nerve. Anesthesia over the face, evaluated by a Semmes-Weinstein monofilament which exerted a force of 0.05 grams, was present in 19.5% of the cases and 15.9% of the controls. Patients with hypopigmented facial patches were found to have more corneal hypoesthesia than patients who did not have hypopigmented facial patches. The risk of having impaired corneal sensation was three to four times higher in patients with hypopigmented facial patches. This feature can be used to identify decreased corneal sensation among leprosy patients under field conditions where direct estimation of corneal sensation is not advocated.