Microscopic inflammatory changes in colon of patients with both active psoriasis and psoriatic arthritis without bowel symptoms

Objective, To evaluate colonic mucosa of patients with both active psoriasis and psoriatic arthritis (PsA) without bowel symptoms. Methods. Fifteen persons (9 men, 6 women) who had both active psoriasis and PsA without bowel symptoms underwent colonoscopy with multiple biopsies of bowel mucosa. Ten nonhospitalized healthy subjects in followup colonoscopy after resection of benign polyps (8 men, 2 women) took part as a control group. Results. Six psoriatic patients (40%) showed macroscopically normal colonic mucosa. In the remaining 9 reddening was frequently recorded (6 cases), while edema and granular changes appeared less commonly (3 cases each, respectively). Friability was markedly rare (only one case) and bleeding and ulcerations were absent. All 15 patients showed microscopic changes. Increase in lamina propria cellularity (consisting of plasma cells and lymphocytes) and lymphoid aggregates were found in all cases. Active inflammation, evident as neutrophilic polymorph infiltration occurred in 9 patients. Glandular atrophy was found in 3 cases; mucosal surface changes and crypt abnormalities occurred in one case each. No control had macroscopic or microscopic inflammatory changes of bowel mucosa. Conclusion. Bowel mucosa of patients with PsA without bowel symptoms show microscopic lesions even when mucosa appeared macroscopically normal. This result may support a pathogenetic link between skin, joints, and gut in psoriatic patients with arthritis even in the absence of bowel symptoms.