Pilot study: specific immunotherapy in patients with Papular urticaria by Cimex lectularius

Background. Papular urticaria is a chronic allergic reaction induced by insect bites. In México the most common causative arthropods reported are bed bugs, fleas and mosquitoes. Approximately 70% of people who are bitten by Cimex lectularius experience hypersensitive reactions, papular urticaria, extensive erythema, urticaria, and even anaphylaxis has been reported, pruritus is the major complaint, impairing quality of life and sleep. Immunotherapy has been used in mosquito bite papular urticaria resulting in improvement of skin lesions and possibly protecting against reactions to subsequent exposures to mosquitoes. Methods. Children, 4-10 years of age, with recurrent papular urticaria due to bedbugs not responsive to multiple treatments were included. An initial allergy assessment included clinical history, skin prick test (SPT), and specific IgE sensitisation was performed to confirmed bedbug sensitization. Twenty children were randomized to receive subcutaneous specific immunotherapy (SSI) with whole body bed bug extract or conventional treatment. The treatment was carried out over twelve months and the response was assessed using the Dermatology Quality of Life Index (DLQ), the immunotherapy satisfaction questionnaire (ESPIA questionnaire) and the 12-Item Pruritus Severity Scale (12-IPSS). The results from both the treated and control groups were compared. Results. The twenty patients were randomized, 12 to receive immunotherapy and 8 to receive conventional treatment for 12 months. Quality of life improved with a reduction in the DLQI score of 19.83 in the immunotherapy group versus 9 in the conventional treatment group (p = 0.03). Itch improved with a reduction in the 12-IPSS of 16.5 in the immunotherapy group versus 9.63 in the conventional treatment group (p = 0.02). After twelve months of treatment, all 12 patients who received immunotherapy, reported a decrease of persistent cutaneous lesions but the 8 on conventional treatment did not. A mean score of 95.75 (SD 3.3) was recorded for satisfaction with immunotherapy. Conclusions. Patients with papular urticaria by Cimex lectularius receiving allergen immunotherapy for 1 year showed a significant improvement compared with baseline and patients receiving conventional treatment regarding skin lesions, quality of life impairment, intensity of pruritus and satisfaction with immunotherapy.