Use of immunotherapy in the management of presumed anaphylaxis to the deer fly.
BACKGROUND
Anaphylactic reactions to biting insects are generally thought to be rare events. Diagnostic and therapeutic standards for these events are not well documented in the literature.


OBJECTIVE
We describe a case report of a patient with multiple suspected immunoglobulin (Ig)E-mediated anaphylactic reactions to biting insects, specifically deer flies (Chrysops sp.), as well as a successful response to immunotherapy.


METHODS
Prick and intradermal testing with deer fly whole-body extract and measurement of specific IgE were performed to help determine the extent of the patient's hypersensitivity. Immunotherapy was subsequently administered with whole-body deer fly extract.


RESULTS
Skin testing was unable to differentiate between the patient and normal controls. In vitro testing was positive in the study patient but only at a low level. After initiating immunotherapy, the patient had repeated exposures to deer fly bites but failed to develop symptoms consistent with his previous anaphylactic episodes. Followup testing on the patient revealed no significant change in the level of skin reactivity or specific IgE.


CONCLUSIONS
Anaphylaxis consistent with an IgE-mediated mechanism to Chrysops sp. is a real phenomenon and is amenable to immunotherapy for the prevention of life-threatening sequela after exposure. Skin testing using whole-body extract appears to be unreliable. In vitro testing was better able to discern a true sensitivity, although the difference between patient and controls was small.
Hrabak
Todd M
TM
Department of Internal Medicine, USAF Medical Center Keesler AFB, Mississippi 39534, USA. todd.hrabak@keesler.af.mil
Dice
John P
JP
D000485:Allergens / Q000627:therapeutic use; D000707:Anaphylaxis / Q000209:etiology / Q000628:therapy*; D000818:Animals; D004175:Diptera / Q000276:immunology*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis; D007299:Insect Bites and Stings / Q000150:complications*; D008297:Male; D008875:Middle Aged
D000485:Allergens