Title: Role of Patch Test in the Etiological Diagnosis of Chronic Urticaria
Authors: Dr Kirti Makhija, Dr Ghanshyam Verma, Dr Ajeet Negi, Dr.G.R.Tegta, Dr Vinay Shanker
DOI: https://dx.doi.org/10.18535/jmscr/v5i4.24
Abstract
Chronic urticaria is one of the enigmas in dermatology and exact etiology is controversial. Chronic urticaria can be ascribed to autoimmunity, reactions to food additives and illness including chronic infection, however approximately 50% of cases still remain unexplained. Even extensive panel of screening investigations added little to the diagnosis of chronic urticaria. Contact sensitization may play a role in the etiopathogenesis of chronic urticaria. Interestingly, many patients of chronic urticaria do not exhibit the physical signs for contact allergy. Patch test for contact sensitization can be helpful in the management of chronic urticaria. The present study evaluated the role of patch testing for the etiological diagnosis of chronic urticaria.
Material and Methods: This study recruited 100 patients with the clinical diagnosis of chronic urticaria, attending the outdoor patient department, with exclusion of children, pregnant and lactating mothers, patients of acute urticaria, urticarial vasculitis, SLE, and on immunosuppressive drugs. Patients were patch tested with Indian Standard Series allergens approved by Contact and Occupational Dermatitis Forum of India.
Results: We observed positive patch test reactions for various allergens in 32% of chronic urticaria patients. There was female preponderance with 55% of the patients. Majority of the patients (34%) were in the age group of 41-50 years. There was a wide range of duration of urticaria from 1.5 months to 360 months (30 years). Most of the patients (29%) presented to us within 7 months to 1 year duration. Nickel was the most common allergen (24%), followed by fragrance mix (12%). Contact sensitivity to Paraphenylenediamine (PPD) and myroxylon pereire resin were found in 2% patients each and epoxy resin; neomycin, cobalt, nitrofurazone, 2-mercaptobenzothiazole, benzocaine and thiuram mix in 1% each. Eighteen patients (18%) had positive reactions to a single allergen, 12% patient revealed sensitivity to two allergens and 2% patients had positive reactions to three allergens.
Conclusion: Patch test, which is originally used for the etiological diagnosis of contact dermatitis, can be employed to know the cause of chronic urticaria, being safe, simple, inexpensive and reasonably sensitive.
Keywords: chronic urticaria, angioedema, patch test, sensitizers, contact dermatitis.
