Increased Prevalence of Bipolar Disorders in Hidradenitis Suppurativa: More Than a Striking Co-existence?

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder of the hair follicle characterized by intense discharge and pain. Recently, HS intrinsic association with neuropsychiatric disorders has become a focus of attention, and bipolar disorder (BD) emerged as a relevant topic for such an association.

This study aimed to evaluate BD prevalence among HS patients and present the HS and BD overlap patients demographics, detailed clinical characteristics with a discussion on aggravating factors.

A retrospective chart review of 247 HS outpatients (Group-1) identified nine patients with BD. The frequency of BD in HS patients is compared to psoriasis patients (Group-2) and controls (Group-3) in age- and gender-matched groups. The demographic and clinical features of the 9 patients revealing HS-BD co-existence were analyzed.

BD (N = 9) was the 7^th most common co-morbidity in the HS cohort. The frequency of BD is detected as 3.6% in group 1, 0.7% (N = 1) in group 2, and 0.6% (N = 1) in group 3, respectively. Group 1 demonstrated an increased prevalence of BD compared to other groups (P = 0.001). Of the 9 patients revealing HS and BD co-existence, 66.6% were active smokers, 66.6% were obese and 44.4 % had metabolic syndrome.

This study results reveal that the prevalence of BD in HS patients is higher than psoriasis patients and controls. The pathogenetic mechanisms underlying BD and HS co-existence needs to be investigated further.