In a study investigating the relationship between hidradenitis suppurativa and alopecia areata in a U.S. sample, those with hidradenitis suppurativa had a significantly higher risk for alopecia of any type and also lichen planopilaris.
“Both [alopecia areata] and [hidradenitis suppurativa] likely involve an inciting event at the hair follicle, which leads to subsequent inflammation,” Joslyn S. Kirby, MD, MS, MEd, of the department of dermatology at Penn State Milton S. Hershey Medical Center in Hershey, Pennsylvania, and colleagues, wrote.
The hidradenitis suppurativa (HS) group comprised patients aged at least 12 years with two separate HS-related claims in an 18-month period. The age- and sex-matched control group included randomly selecting individuals at a ratio of 10 controls to every one patient in the HS group. Controls were never diagnosed with HS, pilonidal cyst, acne conglobata or dissecting cellulitis of the scalp during the same period.
The researchers identified 36,450 matched controls and 3,645 patients with HS.
The HS group had a significantly higher risk for any alopecia areata (RR = 2.22), including alopecia totalis or universalis (RR = 2.17), when compared with the control group. Researchers also discovered an increased risk for lichen planopilaris (RR = 1.54) in patients with HS.
Hypothyroidism and Down syndrome were also associated with HS (RR = 1.17 and RR = 11.46, respectively). After controlling for these potential confounding factors, the RR for alopecia areata was still elevated (RR = 2.09; (95% CI, 1.69-3.2), according to the study.
“In support of this hypothesis, the lesions of both HS and [alopecia areata] patients have considerable overlap in the expression of key inflammatory cytokines,” Kirby and colleagues wrote.
Limitations of the study include a lack of clinical outcome data, temporal association and detection bias in skin conditions, the researchers wrote. – by Abigail Sutton
Disclosures: The authors report no relevant financial disclosures.