Title Unraveling Allergy-Related Factors Contributing to Hair Loss

Background Frontal Fibrosing Alopecia, Lichen Planopilaris, and Central Centrifugal Cicatricial Alopecia are inflammatory alopecias that can be challenging to treat. Previous studies showed LPP and FFA patients are significantly more likely to have positive patch tests and evidence of allergic contact dermatitis. Allergen avoidance improved scalp inflammation. Those studies did not include CCCA common in people of African descent. The purpose of this study was to determine if our data at one institute was similar to previous studies, while including CCCA patients.

Methods A retrospective chart review was conducted on all hair loss patients who received patch testing from January 2021 to June 2023 at KMC Dermatology in Mission, Kansas. Patients were stratified based on diagnosis of FFA, LPP, or CCCA, patch testing, allergens, and anti-inflammatory therapy.

Results 46 of the 80 total patients (57.55%) had a positive patch reaction. Of the 48 LPP patients, 30 (62.5%) had a positive reaction. The majority of the patients that tested positive had LPP (30 of 46). Of the 10 FFA patients, 7 (70%) had a positive reaction. Of the 9 CCCA patients, 5 (55.56%) had a positive reaction. The most common allergen was toluenediamine sulfate (6 patients, 7.5%).

63 of the 80 (78.75%) total patients received anti-inflammatory therapy. Of the 48 patients with LPP, 39 (81.25%) received anti-inflammatory therapy. Of the 10 patients with FFA, 7 (70%) received anti-inflammatory therapy. Of the 9 patients with CCCA, 8 (88.89%) received anti-inflammatory therapy. The most common anti-inflammatory was Doxycycline (34 patients, 42.5%).

Conclusion 57.5% of patients had a positive reaction. Similar to previous studies, a significant number of patients had a positive patch test. It demonstrated the most common allergens were toluenediamine sulfate, benzoyl peroxide, and propylene glycol. Previous studies lacked CCCA and including these patients offers insight on this understudied disease. 55.56% CCCA patients were patch test positive, with the most common allergen being propylene glycol. 78.75% of patients received anti-inflammatory therapy. The most common were Doxycycline, Naltrexone, and Tofacitinib. Lower magnitude of reaction to the patch testing can result if the patient is on anti-inflammatory medication. It’s possible that a reduction in positive results occurred as a large majority of the patients received these medications. Overall, the study confirmed that patients with LPP, FFA, and CCCA can benefit from patch testing evaluation. Encouraging patch testing in these patients, may help to identify allergic triggers, potentially limiting further hair loss.