Same old peristomal dermatitis, but what's causing it?

Abstract

Introduction Prevalence of peristomal dermatoses ranges between 6-80% 1 and more commonly affects patients with urostomies and ileostomies, than with colostomies. Most common causes include irritant contact dermatitis from urine/faeces, mechanical dermatitis, chronic papillomatous dermatitis, seborrheic dermatitis and allergic contact dermatitis. We report an unusual case of allergic contact dermatitis to printing ink on stoma bag which has not knowingly been reported before. Case description A 66-year-old male, presented with a pruritic rash under colostomy bag, not responding to topical emollients and steroids. Examination findings were of an eczematous rash with no obvious leak at stoma site or from bag. He was not on any medication such as Nicorandil which might be contributing to peristomal dermatitis/ulceration. Provisional diagnoses were allergic contact dermatitis and irritant contact dermatitis. First patch test for standard european battery was negative. Histopathology had shown eczematoid spongiotic dermatitis, consistent with allergic/irritant contact dermatitis. He was treated with several emollients, topical Trimovate®, Betnovate® and topical 0.1%Tacrolimus; however, it had made no significant difference even by occlusion with hydrocolloid dressing. Subsequently he was patch tested with colostomy bag tied on to forearm for a week. It was divided in five patches: 1.Inner sticky pad 2.Outer sticky pad 3.Bag 4.Printed area of bag and 5.Joined area of bag. Surprisingly he had shown strongly positive reaction only to number 4 but not to any other part of the bag. It was thought that he was allergic to that particular ink and not to bag itself as he did not show any reaction to un-branded part of the bag. He was advised to cover the printed under surface of the colostomy bag with Micropore® and to continue Hydromol® as barrier emollient and Mometasone furoate ointment for flare ups. His problem completely resolved with covering inked part of colostomy bag with Micropore® and he was discharged back to GP. Enquiry had been made to manufacturer regarding materials used in ink, as patch test for standard European battery were negative, however manufacturer of the colostomy bag had passed it on to the manufacturer of the ink and no further information had been received to this date. Conclusion Allergic contact dermatitis had been reported secondary to ostomy bag/pouch, sealing rings, strapping, deodorizers, adhesives, skin cleansers and topical emollients and ointments. Patch testing had always been the key investigation in these cases. Most reported cases had shown sensitivity to ‘epoxy resin' which is a component of stoma bag itself. Allergic contact dermatitis had also been reported to karaya gum seal ring 2 , colophony & benzyl peroxide 3 , tinuvin P® / 2-benzotriazol 4 , di-aminodiphenylmethane and rubber seal surrounding the bag 5 . Other cases had shown sensitivity to adhesive tapes, polyisobutylene (adhesive ring of ostomy bag), adhesive remover wipes, stomahesive paste®, dansac® soft paste, gantrez ES®, balsam of Peru, cinnamic aldehyde, geraniol, benzyl alcohol, isoeugenol, propylene glycol and DOR ostomy deodorant® 6 . However, so far we had not noted any case report showing sensitivity to printing ink on colostomy bag. It is unfortunate that we are still unable to get the information on components of ink however, in suspected cases it would be worth covering the printed under surface of colostomy bag to overcome possible allergic contact dermatitis. Recommending manufacturers of stoma care products to avoid printing on the surface in contact with the skin would also be another feasible alternative. Take-home message 1.Allergic contact dermatitis is one of the common causes of peristomal dermatitis. 2.Patch test is important if allergic/irritant contact dermatitis is suspected. 3.Stoma bag can be used directly for patch testing if commercially available patch tests batteries do not show any positive result. 4.Although quite rare, patients can develop sensitivity to printing ink on stoma bag and covering printed surface can be considered if clinically suspected.