Background: Severe skin reactions to mosquito bites are immune mediated, involving IgE, IgG, and T lymphocytes in response to allergens in mosquito saliva. Chronic active EBV infection may result in bullous and ulcerative skin reactions to mosquito bites. The pathogenesis involves infected NK cells activation by mosquito saliva-specific CD4+ lymphocytes. One patient with severe ulcerative skin lesions induced by mosquito bites after infectious mononucleosis with NK lymphocytosis was seen previously in our clinic.
Objectives: To evaluate the clinical presentation and prevalence of positive EBV serology in children with severe skin reactions to mosquito bites.
Methods: Since 7/2011 all children referred for evaluation of "mosquito bites allergy" underwent blood tests for CBC, IgE and EBV serology. Clinical and laboratory data were retrieved from the medical records in 11/2013.
Results: 33 children were evaluated: 17 males, age range 1.1-9.6 years (mean-3.8 years), atopic dermatitis in 10 (30%). All had papular/vesicular skin lesion/large local reactions. Ten had secondary infection and were admitted for iv antibiotics; Two of these patients had additional systemic symptoms (prolonged fever, tonsillitis, cervical lympadenopathy, elevated liver enzymes), and in one, EBV sero-conversion was demonstrated. Twenty six (79%) patients had eosinophilia (600-3300/mm3). Mean IgE levels were 3851±5076 IU/ml (range: 52-15100 IU/ml). Positive EBV IgM was found in 3 patients and positive EBV EBNA IgG was found in other 11 patients. NK cells numbers were normal in 4 patients tested for lymphocytes subpopulations.
Conclusions: Eosinophilia and high IgE levels are prominent features of severe skin reactions to mosquito bites, with or without evidence for EBV infection.
