A patient with severe black fly (Simuliidae) hypersensitivity referred for evaluation of suspected immunodeficiency.
BACKGROUND
Biting flies of the Diptera order and specifically the black fly (Simuliidae family) can be rare causes of severe hypersensitivity reactions.


OBJECTIVE
To describe a patient referred for evaluation of immunodeficiency whose clinical course is explained by severe Simuliidae hypersensitivity.


METHODS
The patient's immune system was investigated using standard laboratory evaluations. Hypersensitivity to Simuliidae was pursued because of historical features of her presentation and was specifically examined by skin prick and intradermal testing with whole body extract.


RESULTS
The patient's history was notable for recurrent and severe seasonal episodes of presumed cellulitis after black fly bites that responded poorly to intravenous antibiotics. One episode was followed by acute inflammatory demyelinating polyneuropathy (Guillain-Barré syndrome) and another by minimal change nephrotic syndrome. The results of immunologic investigations were unremarkable, but cutaneous hypersensitivity to Simuliidae was demonstrated with a 6.5-mm wheel and 35-mm flare reaction to intradermal injection of only 0.0005 microg of whole body extract.


CONCLUSIONS
Similar to Hymenoptera, Simuliidae can rarely result in extreme hypersensitivity and should be considered in appropriate cases. This patient illustrates how severe reactions toinsect bites can be misdiagnosed.
Department of Pediatrics, Harvard University Medical School, Children's Hospital, Boston, Massachusetts 02115, USA.
Jordan S
JS
Orange
Leslie A
LA
Song
Frank J
FJ
Twarog
Lynda C
LC
Schneider
D000818:Animals; D000890:Anti-Infective Agents / Q000627:therapeutic use; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D002481:Cellulitis / Q000188:drug therapy / Q000276:immunology; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000188:drug therapy / Q000276:immunology*; D007153:Immunologic Deficiency Syndromes / Q000175:diagnosis / Q000276:immunology*; D007299:Insect Bites and Stings / Q000188:drug therapy / Q000276:immunology*; D008404:Massachusetts; D012424:Rural Population; D012843:Simuliidae / Q000276:immunology*
D000890:Anti-Infective Agents; D000893:Anti-Inflammatory Agents