Cutaneous and oral comorbidities in patients with geographic tongue: a multicenter multidisciplinary cross-sectional observational study

Geographic tongue (GT) represents a localized type of psoriasis inversa and its burden of dermatological and oral comorbidities frequently conditions its severity and diagnosis. Currently, no epidemiological studies have evaluated GT muco-cutaneous comorbidities. We aimed to study oral and dermatological comorbidities in a large sample of GT patients. In this multicenter, cross-sectional study, involving 4 primary referral centers in Italy, we evaluated adult GT patients, who were assessed by board certified dermatologists and dentists for 5 months and collected demographics and medical history. GT was evaluated using Hume's classification together with Geographic tongue severity index (GTASI) to score its severity. The prevalence of oral and dermatological comorbidities was recorded. In the sample we enrolled 137 GT patients (M/F= 5:1) with a mean age of 48,2 ± 14,7 yoa and 33.6% had GT family history. The clinical evaluation found 96 (70.1%) GT type I, 7 (5.1%) type II, 13 (9.5%) type IIIa, 19 (13.9%) type IIIb, 2 (1.5%) type IV, following Hume's classification. The mean GTASI score was 23,7 ± 14,2 and the vast majority displayed a severe form of GT. Eighty-nine patients had oral comorbidities (burning mouth syndrome, caries, parulid and lichen planus) and 80 had dermatological concurrent conditions (plaque psoriasis, inverse psoriasis and atopic dermatitis). In GT patients, both dermatological and dental evaluation should be mandatory to identify previously undiagnosed mucocutaneous comorbidities.