Pemphigus and associated comorbidities: a cross-sectional study

Pemphigus is a rare autoimmune blistering disease, reported to be associated with other coexisting and autoimmune diseases, including thyroid diseases, rheumatoid arthritis, alopecia areata, vitiligo, systemic lupus erythematosus, scleroderma and rare entities such as myasthenia gravis.

To identify and describe patients with pemphigus with a diagnosed comorbidity, and to quantify the risk of additional comorbidities.

This was a cross-sectional study of patients with pemphigus treated at a tertiary referral centre. Prevalence rates of 15 comorbid diseases were calculated. Age-standardized prevalence ratio (SPR) and 95% CI were calculated in comparison with prevalence rates in the general Canadian population using data from the Canadian Community Health Survey. Data were analysed using SAS software.

In total, 295 patients were identified. An increased risk of hypothyroidism (n = 38, SPR = 1.53, 95% CI 1.08-2.10) and inflammatory bowel disease (IBD) (SPR = 1.48, 95% CI 0.40-3.80), and a two-fold increased risk of diabetes (SPR = 2.20, 95% CI 1.64-2.87) were observed.

Patients with pemphigus have a higher incidence of hypothyroidism, IBD and diabetes compared with the general population. As part of pemphigus investigations and surveillance, investigating for these conditions may be considered.