Abstract
Apical periodontitis is an inflammatory response of periradicular tissues caused by microbial infection within the root canal system. Alopecia areata (AA) is a T‐cell mediated, autoimmune condition affecting hair follicles causing nonscarring hair loss, clinically characterised by small patches of baldness on the scalp and/or around the body. Although there have been links to genetic, environmental and hormonal triggers, this condition has rarely been associated with oral infection. This report presents three cases of AA with no obvious aetiology in fit and healthy patients, whereby the alopecic patches appeared coincident with apical periodontitis. The first case describes complete resolution of AA after successful non‐surgical retreatment of the LR6 with apical periodontitis after 3 years. The second case was followed up for 9 months, with a complete healing of AA following the affected tooth extraction, whereas the third case demonstrates complete hair regrowth after 4 months following the single‐visit endodontic therapy. This article highlights the impact of oral infection on endogenic immune‐inflammatory mediators, although causality cannot be inferred from these observations alone. There is a need for an interdisciplinary approach in cases of idiopathic AA, in the absence of other aetiological factors, to preclude unnecessary pharmacological interventions. Due to these limitations, more epidemiological studies would be beneficial to investigate any possible association between AA and apical periodontitis.