Trachyonychia (rough nails).

The term trachyonychia is a useful one to describe roughening of the surface of many nails due to various causes. Psoriasis and alopecia areata are responsible for some cases. Lichen planus can roughen nails but the change is usually limited to a few nails and accompanied by discomfort. In many cases no cause can be found and these cases are somewhat arbitrarily listed either as twenty nail dystrophy of childhood or severe nail dystrophy.

Familial lichen planus. Another disease or a distinct people?

When lichen planus strikes families, a very rare happening, it is likely to afflict younger members, to erupt more acutely, extensively, and gravely, attacking also nails and mucous membranes, and to recur. Ten patients with familial lichen planus, two each from five distinct Caucasian families, the parents of whom were unrelated by birth, were found to be carrying HLA-B7 statistically more frequently than in the normal population or in those with the characteristic forms of lichen planus. We hint that their genotype might have rendered them susceptible to a pathogen that precipitated their disease.

Chronic superficial dermatitis and poikiloderma.

The terms chronic superficial dermatitis and poikiloderma have in the past both been called parapsoriasis en plaques although they are entirely different disorders. Chronic superficial dermatitis is benign and does not advance to a reticulosis. Poikiloderma of the prereticulate type, on the other hand, may progress and may be the cause of death in some cases. It should no longer be considered a separate entity but should be regarded as part of the spectrum of mycosis fungoides.