[Oral lesions in psoriasis]

The literature contains little information about the incidence or prevalence of oral signs in psoriasis. The pustular forms are the most commonly incriminated, with geographic tongue being the most frequently cited oral sign. The aim of our study was to determine the various types of oral signs seen in a large population of psoriasis patients.

Four hundred psoriasis patients were recruited consecutively and a detailed oral examination performed by two clinicians. Similar examinations were performed over the same period in 1000 nonpsoriasis subjects comprising a control group in order to assess the incidence of the same oral signs in the general population.

Comparing the two groups, fissured tongue was seen in 33.2% of psoriasis patients versus 9.9% of control subjects (P<0.0001). There was thus a highly significant (P<0.0001) correlation between geographic tongue and psoriasis (7.7% of psoriasis patients versus 1% of controls). In addition, a strong correlation was seen between the presence of pustular psoriasis and fissured tongue (83.3% of patients with pustular psoriasis versus only 30% of patients with other forms of psoriasis).

Our study shows a strong correlation between psoriasis and fissured and geographic tongue, although these features are not pathognomonic for the disease. As regards geographic tongue, our results are consistent with the data in the literature. However, the prevalence of fissured tongue was considerably higher among our patients than in series published to date. These two types of sign involving the tongue, and which can occur in all forms of psoriasis, appear to be particularly strongly associated with pustular psoriasis. Patients are generally unaware of this sign and rarely complain of it.