Psoriasis and vitiligo are close relatives

BACKGROUND Both vitiligo and psoriasis are chronic inflammatory autoimmune diseases with genetic elements. OBJECTIVE To estimate the frequencies of psoriasis in vitiligo patients and vice versa and to compare them with healthy controls. PATIENTS AND METHODS A total of 1000 subjects were included, 250 of them had vitiligo, 250 had psoriasis, and 500 were healthy controls. Measurement of the frequencies of vitiligo in psoriatic patients and psoriasis in vitiligo patients was carried out. Thereafter the frequencies of both diseases were assessed in healthy controls. The frequency of vitiligo among psoriatic patients was compared with that of vitiligo in healthy controls. A similar comparison was done between the frequency of psoriasis among vitiligo patients with that in healthy controls. Other comparisons were performed between the frequency of family history of psoriasis among vitiligo patients with that in healthy controls and between the frequency of family history of vitiligo in psoriatic patients with that in healthy controls. RESULTS The frequency of psoriasis among vitiligo patients was 15 (6%) and among healthy controls was 2 (0.4%); there is a statistically significant difference (P=0.001). The frequency of vitiligo among psoriatic patients was 5 (2%) and among healthy controls was 3 (0.6%); no statistically significant difference was found (P=0.16). The family history of psoriasis among vitiligo patients was 23 (9.2%) and among healthy controls was 20 (4%); there is a significant association (P=0.043). The family history of vitiligo among psoriatic patients was 24 (9.6%) and among healthy controls was 40 (8%); the difference is statistically significant (P=0.042). CONCLUSION The present work has confirmed the close relationship between vitiligo and psoriasis.