RESUMO
To evaluate any association between various ABO blood types and different dermatoses, viz, psoriasis, vitiligo, alopecia areata and pemphigus vulgaris. This hospital-based, case-control study involved evaluation of ABO blood typing of 140 cases of psoriasis, 76 vitiligo, 84 alopecia areata and 30 pemphigus vulgaris, and 2067 controls. O blood group was found in 37.1% patients of psoriasis, followed by blood type B [30%] and blood group A [25.7%], without any significant difference between cases and controls. In vitiligo patients, B blood group was found in 47.4% patients, followed by blood group O [36.8%] and blood group A [10.5%]. The results between vitiligo patients and controls regarding blood group A and B were statistically significant. In alopecia areata patients, blood group B was found in 45.2% patients, followed by blood group O [28.6%] and blood group A [19%], the difference being not statistically significant. In pemphigus vulgaris patients, O and B blood group were found in 40% patients each, followed by blood group A [20%], but this was not statistically significant. In psoriasis patients in our study, blood group O was the most common, but without any statistical significance than the controls. In vitiligo patients, B blood group was the most common and this was statistically significant. Difference in the blood group A, although found less frequently than B and O blood group, was also statistically significant between study group and controls. In alopecia areata, B blood group was the most common, but this finding was not statistically significant when compared to controls. In pemphigus patients, blood group O and B were equally common, but this was not statistically significant than the controls.