Malabsorption in psoriatic patients: cause or consequence?

OBJECTIVE: The etiopathogenesis of psoriasis is still unclear. Associations between gut and skin diseases are well known, since psoriatic patients show a high prevalence of coeliac disease. Small-bowel abnormalities can cause clinical or, more frequently, laboratory alterations that give rise to malabsorption. The aim of the study was to evaluate the prevalence of malabsorption in psoriatic patients. MATERIAL AND METHODS: Fifty-five (29 M, 26 F, mean age 51+/-8 years) psoriatic patients in the Dermatology Centre of our hospital and 65 healthy controls (36 M, 29 F, mean age 47+/-9 years) were screened for malabsorption using a D-xylose test. Psoriatic subjects who resulted positive were further investigated in order to reach a better characterization of the malabsorption using serum antigliadin, anti-endomysium and anti-transglutaminase antibodies, H2 lactulose breath test, the parasitological faecal test and colonoscopy with retrograde ileoscopy. RESULTS: Altered D-xylose absorption was found in 60% (33/55) of psoriatic patients and in 3% (2/65) of controls. Of the former, 6% had coeliac disease, 21% had bacterial overgrowth, 3% had parasitic infections and 1 patient presented eosinophilic gastroenteritis. CONCLUSIONS: Malabsorption was more prevalent among psoriatic patients than among controls. Coeliac disease, bacterial overgrowth, parasitic infestations and eosinophilic gastroenteritis could be possible causes of malabsorption in these patients. Further studies are needed to clarify the pathogenesis and possible causative associations between gut and skin diseases.