Allergic contact dermatitis (ACD) is a rare cause of peristomal skin problems. Only 23 cases have previously been reported in the literature. We report the case of a colostomy patient with a severe disabling blistering peristomal dermatitis. Patch testing to a British Contact Dermatitis Society standard series, medicaments and a plastics and glues series was negative. Patch testing to the patient's own products gave a positive reaction (+) at D2 and D4 to Dansac® soft paste and Stomahesive® paste. Further patch testing to the components of Dansac® soft paste showed a positive (+) reaction at D2 and D4 to ester of polymethyl vinyl/maleic acid copolymer (Gantrez®-ES) only. This is the first reported case of ACD due to Dansac® soft paste. ACD to Gantrez® has previously been reported but in different products. We also review the other previously reported cases of ACD causing peristomal dermatitis and stress the importance of patch testing in these cases, in particular to the patient's own products, as avoidance of identified allergens can have a large impact on the quality of life.