Ladakhi koilonychia.

A total of 176 highlander Ladakhis staying at an altitude of 3445 meters were examined for nail changes. Mean age of the subjects was 22.28 years (range 3-58 years). Koilonychia was seen in 47.16% of the subjects. It was most common during fourth (80.56%) and fifth (80%) decade. Males (49.60%) were slightly more commonly affected than females (41.34%). Soldiers (69.57%) were most commonly affected. Peasant and labourers (64.26%) were also equally affected. Most of the soldiers were also involved in forming during their leave period. Recruits (39.29%) and students (30.30%) were less commonly affected. Right index finger (36.36%), right middle finger (30.68%) and right thumb (29.55%) finger nails were most commonly affected followed by left thumb (13.64%), left index finger (10.23%), right ring finger (8.52%) and left middle finger nails (7.95%). Mean haemoglobin levels in those with or without koilonychia were 14.17 and 14.12 gm % respectively. Chronic hypoxia of high of high altitude causing increased erythropoiesis and depletion of iron stores leads to thinning of nail plate and atrophy of the distal nail bed with superadded mechanical trauma of farming or hard labour is the most likely cause of Ladakhi koilonychia. Dietary iron supplementation as a public health programme should be started in Ladakh to meet the demands of increased erythropoiesis in chronic hypoxic conditions.