In search of oral psoriasis
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- Yesudian, P.D., Chalmers, R.J.G., Warren, R.B. et al. Arch Dermatol Res (2012) 304: 1. doi:10.1007/s00403-011-1175-3
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Even though psoriasis is a common skin disorder, reports of it involving the oral cavity are exceedingly rare, with less than 100 publications in the literature. Biopsy-proven oral psoriasis has been reported in the oral medical literature, but the commonest oral mucosal findings in most studies are associated non-specific features including fissured and geographic tongue. Case series on this entity have not provided any definitive data to support its existence. From the evidence available to date, it is still unclear if oral psoriasis is a distinct entity or if, indeed, it exists.
KeywordsOral psoriasisOral manifestations and psoriasisMucocutaneous psoriasis
Psoriasis is a common inflammatory skin disorder that affects around 2% of the UK population . Although the cutaneous manifestations of psoriasis are well described, there are limited data about its oral involvement. Initial reports lacked microscopic confirmation of the clinical findings, leading some authors to doubt its existence . Recent reviews have described the clinical features, histological appearances, differential diagnosis and treatment modalities of oral psoriasis (OP) [4, 44]. However, it is still debated whether OP is a distinct entity. The purpose of this review is to dissect out the evidence that could help confirm or refute the existence of OP. We reviewed the literature using the keywords “oral psoriasis”, “oral and psoriasis”, “oral manifestations of psoriasis”, “psoriasis with oral involvement” and “mucocutaneous psoriasis” and collected all the case reports, case series and review articles on the topic using Medline, PubMed, Ovid and Cochrane databases.
The first clinicopathological report of OP was by Oppenheim in 1903 . Since then, there have been less than 100 publications on OP. In 1933, Usher examined 100 patients with cutaneous psoriasis and found involvement of the buccal mucosa in two of them . DeGregori et al.  noted that until 1971 only 15 cases of intraoral psoriasis had been recorded, of which three involved the gingival tissues . The first significant prospective series  involved the examination of 200 consecutive patients with cutaneous psoriasis; 20 patients had oral mucosal changes, which were then biopsied. Typical psoriatic pathology was found in four of these biopsies. More recent studies involving large cohorts of patients with cutaneous psoriasis have both asserted  and questioned [8, 9] the existence of specific oral lesions in psoriasis. It is generally accepted that patients with acute exacerbations of psoriasis are more likely to develop oral manifestations than those with chronic stable disease [20, 30].
Case series on oral psoriasis
Psoriasis N (%)
Controls N (%)
Psoriasis N (%)
Controls N (%)
Psoriasis N (%)
Controls N (%)
Hernandez-Perez et al. 
Daneshpazhooh et al. 
Morris et al. 
Hietanen et al. 
Costa et al. 
Kaur et al. 
Büchner et al. 
Psoriasis of the vermilion of the lips is rare and usually associated with more typical plaque psoriasis elsewhere . It presents as scaly areas which may extend across the vermilion border . Keratotic lesions have also been described . There have been three cases where involvement of the vermilion of the lip occurred without any intra-oral changes [19, 31]. Büchner and Begleiter noted a relatively high incidence of angular cheilitis (11%) in their series of 100 patients and, as most of those affected were below the age of 35 years, suggested that it was due to the psoriasis itself and not secondary to skin laxity around the oral commissures as found in the edentulous elderly . A larger study, however, did not find the incidence of angular cheilitis to be higher than in 166 matched controls . Psoriasis koebnerising to the vermilion border of the lip following protrusion of the upper teeth has been reported . As the epithelium of the vermilion of the lip is partially keratinised, psoriasis of this site may mirror its occurrence in the skin.
Lesions of the tongue which have been attributed to psoriasis can be divided into two major categories: the first includes mucosal abnormalities with psoriasis-like histology which parallel the clinical course of psoriasis in the skin. It is uncertain if these findings are rare or whether they are overlooked because they are asymptomatic. The second group is much commoner and comprises a range of non-specific lesions including fissured tongue and geographic tongue which are thought to occur more frequently with psoriasis .
Diffuse erythema of the tongue, a non-specific feature, has been described in up to 5.5% of those with psoriasis .
Fissured tongue appears to be the commonest oral finding in OP: studies have reported rates of 6.5%  and 20%  in patients with cutaneous psoriasis. It is believed to be an inherited trait, characterized by an antero-posteriorly oriented fissure with some lateral branching . It affects about 2–5% of the general population, with an increasing incidence with age. Fissured tongue is also found in up to 50% of patients with geographic tongue . Patients with generalized pustular psoriasis are more likely to manifest fissured tongue compared to those with chronic plaque psoriasis .
Geographic tongue or benign migratory glossitis presents as erythematous patches with a raised white or yellow serpiginous border. Lesions can migrate across the tongue by healing in one margin and extending in another. It is present in about 1–5% of the general population , but has been reported in up to 10% of psoriasis patients . Other studies have not supported this association with incidences of only 5.7%  and 1% , respectively. Geographic tongue has been said to be found more frequently in association with generalized pustular psoriasis , though this has been disputed in the recent literature . Dawson has suggested that the presence of geographic tongue in an otherwise normal patient may indicates an increased propensity to develop generalized pustular psoriasis . One study showed a significant association of HLA-Cw6 with both psoriasis and geographic tongue, lending credence to a pathogenic relationship between the two conditions .
Lesions of the buccal mucosal attributed to psoriasis are annular, serpiginous, or polycyclic papules and plaques that are prominent during flares of the cutaneous disease . Whitish and erythematous plaques have been observed in up to 3.5% of a cohort of 547 patients . Erythematous patches have been reported to occur less frequently, and “erosions”, which tend to be areas of atrophy rather than breaks in the mucosa are rare . The terms ectopic geographic tongue, stomatitis areata migrans, erythema circinata migrans, geographic stomatitis or migratory stomatitis have been used to denote this condition . It is similar to geographic tongue, but occurs on the buccal mucosal surface instead. The reported frequency of this finding has varied from 0–19% of psoriasis patients . Patients with erythrodermic psoriasis have had histological analysis of their buccal mucosa and this has shown increased dermal vascularity with an inflammatory cell infiltrate that reduced following treatment of the psoriasis .
White lesions as well as red, serpiginous, concentric arcs have been reported on the palate of patients with psoriasis . Palatal lesions tend to show whitish semitransparent plaques rather than the typical silvery scales seen on the skin. Erythematous patches with or without ulceration, which are analogous to the aforementioned ectopic geographic tongue, have also been reported .
Gingival involvement appears to be rare compared to the other oral manifestations. Erythema of the gingival margin and the presence of white reticular plaques extending from the erythema have been noted. Periodontitis with sharply demarcated erythematous gingival plaques has been attributed to psoriasis [38, 41].
Pathology and pathogenesis
Histology of purported OP shows hyperkeratosis or parakeratosis, elongation and clubbing of the rete ridges, thinning of the supra-papillary epithelium, and a chronic inflammatory infiltrate which is either lymphocyte or neutrophil dominated, dependent on the stage of evolution of the lesion. Munro’s micro-abscesses and spongiform pustules of Kogoj have also been seen with the former observed predominantly in early lesions . However, these features have been reported to occur less commonly in the oral mucosa than in psoriatic skin . Furthermore these histological features, which have been termed psoriasiform mucositis, are non-specific and are also seen in Reiter syndrome, geographic tongue and ectopic geographic stomatitis .
Significant advances have been made in the understanding of the pathogenesis of psoriasis, a complex inflammatory disease influenced by both genetic and environmental factors . It is characterized by inflammation that in turn leads to epidermal hyperproliferation. However, the oral mucosa is morphologically and immunohistologically distinct from the keratinised stratified squamous epithelium of the skin. This may explain why it appears to be involved only rarely, if at all, in psoriasis. Differences in cell surface carbohydrate expression between oral squamous epithelium  and the epidermis have been proposed as a potential explanation. Importantly, genetic studies have indicated that an allelic variant of corneodesmosin, a late differentiation epidermal glycoprotein putatively involved in keratinocyte adhesion, has a strong association with psoriasis . If the presence of corneodesmosin, which is absent from oral mucosal epithelium, is shown to be a prerequisite for the development of psoriasis, then the scarcity of reports of OP would not be surprising. Even though oral epithelium is exposed to a variety of bacterial products and allergens derived from food, chronic allergic inflammatory reactions are infrequent . Oral Langerhans cells express FcεRI, which increases production of the anti-inflammatory cytokines interleukin-10 (IL-10) and transforming growth factor-β1, thereby inducing tolerance to foreign antigens. Such immune mechanisms might be involved in protecting oral mucosa from the development of psoriasis .
Strict criteria for the diagnosis of OP have been proposed. These include: clinical course of the oral lesions that parallel the skin manifestations, a positive family history of cutaneous psoriasis, clinicopathological correlation, the presence of appropriate HLA typing (most frequently associated HLA antigens are B13, B17, B37, Cw04, and Cw06), and exclusion of similar oral conditions .
The differential diagnoses of OP are many and include Reiter syndrome, oral candidiasis, secondary syphilis, lichen planus, lupus erythematosus, pemphigoid, pemphigus and leukoplakia [6, 44]. The lip lesions and fissured tongue may resemble Melkersson-Rosenthal syndrome. Isolated lip involvement may be confused with actinic cheilitis or chronic eczema. Other mucosal changes that could mimic OP may result from habitual smoking, poor-fitting dentures, or cheek biting . A biopsy is essential in establishing the diagnosis. In the absence of cutaneous lesions, immunopathology may be helpful in excluding the immunobullous disorders. Even then there must be some doubt as to whether OP exists.
Given the high prevalence of psoriasis, intra-oral lesions are rarely reported. Almost any part of the oral mucosa has been reported as being affected, with lesions described on the tongue, palate, buccal mucosa, lips and gingivae. Fissured tongue and geographic tongue are the main features that have been closely linked with psoriasis.
Overall, the case for the existence of OP is underwhelming. Thus, we believe it is open for debate as to whether OP is a distinct entity. Most publications are in the oral medical literature with few reviews by dermatologists. A prospective clinical study focusing on this enigmatic condition involving a multi-disciplinary collaboration between Oral Medicine and Dermatology may provide a definitive answer.
RBW is an NIHR Clinical Senior Lecturer. CEMG is partly supported by the NIHR Manchester Biomedical Research Centre.
Conflict of interest
There are no competing interests for any of the authors in preparing this manuscript.