Anaphylactic reaction following forest fly (Hippobosca equina) bite: A human case

The authors report the case of a 46-year-old female patient, who experienced an anaphylactic reaction with a lucky outcome following an insect bite. Within a short time, a hard swelling of 15-cm diameter, covered by a serous crust, appeared at the border of her forehead and hairy scalp, with oedema on her forehead. Soon thereafter, erythema and itching developed locally and all over her body, with oedema of her hands, face and lips, later accompanied by shivering, nausea and vomiting. Based on identification with the help of a taxonomic key, the captured insect proved to be a forest fly (Hippobosca equina). As far as we know, this is the first published case of anaphylaxis induced by the bite of this species in Hungary. Forest flies are present all over the world; they have been known in Hungary for a long time; they suck blood several times a day mostly from horses, donkeys or cattle kept on pastures or in stables and cowsheds, and occasionally also from other animal species. As vectors, they transmit various pathogens. By reporting our case, we wish to call the attention of family doctors and clinicians to horse tick bite and the clinical signs and symptoms caused by it, since they have no specific experience required for the diagnosis of such insect bites.