Variation in mast cell numbers in psoriasis and lichen planus: comparisons with normal skin

This study has examined the influence of age, sex, and site on the numbers of mast cells in normal human skin from 60 healthy Indian volunteers. 5-microns-thick paraffin-embedded sections were stained with 0.001% toluidine blue and the mean number of mast cells per mm3 estimated. Multivariate analysis of variance revealed significant effects of age, site and sex upon mast cell numbers with greater numbers in the facial skin of young females compared with arm skin of young patients of both sexes and older females. Mast cell numbers were also significantly higher in both involved and uninvolved skin of patients with psoriasis in contrast with increased numbers in involved skin only, observed in lichen planus. This is the first report of mast cell density in Indian Caucasian skin.