ABSTRACT

Psoriasis presents in various forms involving different parts of the nail unit as shown in Table 3.1.

PITS These are the commonest signs in psoriasis. They are mainly seen on fi ngernails. They are deeper than those in alopecia areata and also more numerous. They are due to involvement of the proximal part of the nail matrix, resulting in abnormal cornifi cation and presence of parakeratotic corneocytes in the nail plate. These cells, as they are loosely attached, drop out leaving punctuate depressions on the nail plate (resembling a thimble), which correspond to the pits (Fig. 3.1).