Nail changes in the common dermatoses
Most patients with psoriasis have nail changes at some stage; severe nail involvement is more likely in the presence of arthritis. The best-known nail change is pitting of the surface of the nail plate (Fig. 5.7). Almost as common is psoriasis under the nail plate, showing up as red or brown areas, often with ony-cholysis bordered by obvious discoloration (Fig. 5.8). There is no effective treatment for psoriasis of the nails.
Some patients with itchy chronic eczema bring their nails to a high state of polish by scratching. In addi-tion, eczema of the nail folds may lead to a coarse irregularity with transverse ridging of the adjacent nail plates.
Some 10% of patients with lichen planus have nail changes. Most often this is a reversible thinning of the nail plate with irregular longitudinal grooves and ridges.
More severe involvement may lead to ptery-gium in which the cuticle grows forward over the base of the nail and attaches itself to the nail plate (Fig. 13.26). The threat of severe and permanent nail changes can sometimes justify treatment with systemic steroids.
The more severe the hair loss, the more likely there is to be nail involvement. A roughness or fine pitting is seen on the surface of the nail plates and the lunulae may appear mottled.