Diagnosis

The diagnosis is made by paying attention to the coexistence of parasitic disease, and by the microscopical examination. It must not be forgotten that the nails are rendered opaque, thick, and brittle in connection with psoriasis, pityriasis rubra, lichen ruber, and the like; but in parasitic cases the evidence of the connection between the nail and the general disease and the origination of the former from the latter is usually clear.