Patch testing in patients with anal itchingBMJ 2016; 355 doi: https://doi.org/10.1136/bmj.i6269 (Published 28 November 2016) Cite this as: BMJ 2016;355:i6269
- Mohammed J Abu-Asi, doctor and MSc clinical dermatology,
- Jonathan M L White, consultant dermatologist
- Cutaneous Allergy Clinic, St John’s Institute of Dermatology, Guy’s and St Thomas’ Hospitals NHS Foundation Trust, Guy’s Hospital, London SE1 9RT, UK
Thank you for the concise summary article on anal itching.1 Perianal dermatoses and pruritus ani are common and socially embarrassing conditions that are often poorly managed.
Patch testing is important in this group of patients, but published data are lacking. We have published the largest reported case series, carried out in the Cutaneous Allergy Clinic at St John’s Institute of Dermatology.2 We strongly recommend patch testing in all patients with perianal dermatoses or pruritus ani, as approximately 20% of them will have relevant allergens to be avoided.
Patients should be tested with the European baseline series, other relevant series, and the patient’s own products. In our study, methylchloroisothiazolinone/methylisothiazolinone was the most common allergen implicated in pruritus ani, frequently from the use of wet wipes and other toiletries.2
Apart from wet wipes, clinicians should ask about other suspected triggers for perianal disease, such as sanitary towels, haemorrhoid medications, suppositories, toiletry sprays and deodorants, and clothing.
Competing interests: None declared.