**4. Associated diseases**

Several medical conditions have been linked to AA. Skin disorders such as vitiligo, psoriasis, or atopic dermatitis (as well as atopic triad) were more commonly found in AA patients compared with healthy individuals. Furthermore, the association with thyroid disease and lupus erythematosus has been reported [59, 60]. This association is likely due to shared genetic loci and cytokine profiles [31, 32]. Patients with genetic conditions such as Down syndrome and polyglandular autoimmune syndrome type 1 show increased incidence of AA [61, 62]. Psychiatric comorbidities have also been reported in AA patients, but causality remains obscure since hair loss can increase anxiety and mood disorders [63, 64].
