colour changes in nails

Last reviewed 11/2022

The yellow nail syndrome and leuconychia are well characterised conditions.

Green nails result from Pseudomonas infection.It is usually seen in patients with chronic paronychia, onycholysis or onychotillomania and especially in people with abnormal nails who are exposed to wet environment. A fluorescent produced by P. aeruginosa (siderophore pyoverdin) is responsible for the green colour. Treatment is with topical antibiotics (1).

Blue nails often occur as a side effect of anti-malarial drugs eg. chloroquine. An azure - sky-blue - lunula is common in argyria - silver-poisoning - and has been seen in Wilson's disease.

Black nails may be seen in Peutz-Jegher's disease, vitamin B12 deficiency and post-irradiation. Black streaks in the matrix and nail plate may indicate a junctional melanocytic naevus or malignant melanoma.