Red fire ant (Solenopsis Geminata Fabricius) sting can cause allergy from local reactions to anaphylaxis [1]. However, angioedema due to ingestion of cooked ‘flying red fire ants’ in children has not been reported earlier.

An 8-year-old boy was rushed to the pediatric emergency room of our hospital with the complaints of rapidly progressive swelling of within last 5 minutes. Swelling of face was first noticed in lips (Fig.1), periorbital region, ear lobules and then rapidly progressed to entire face. There was no history of breathlessness, pain or itching. There was no rash, but angioedema of face was noted. His vital parameters were normal. Mother gave the history of ingestion of fried flying ants (Fig. 2).

Fig. 1 Angioedema of lips.

Fig.2 Fried flying red fire ants.

The child was treated with intravenous hydrocortisone and antihistaminics. Edema started to decrease after 4 hours of management and the child recovered fully by 24 hours.

Insects of the order hymenoptera, members of genus Solenopsis namely S. invicta, S richteri and S geminate, have a stinging apparatus at the tail end of their abdominal segment and are capable of delivering 100 ng of venom. The venom has various peptide and protein components and some of which are capable of inducing vasoreactive substances. It has been estimated that 1500 stings would be required to deliver a lethal dose of hymenoptera venom for a non allergic adult weighs 70 kg [2]. Ninety-nine percent of the alkaloid component of red fire-ant venom is made up of 2, 6, di-substituted piperidines that have hemolytic, antibacterial, insecticidal, and cytotoxic properties. Venom alkaloids do not generate IgE antibody responses and thus do not appear to be responsible for allergic reactions [3]. Anaphylaxis is more common and severe in subsequent stings [4]. Serious complications like laryngospasm, seizures, rhabdomyolysis and acute renal failure were reported [5].

Allergic angioedema typically occurs within several minutes of exposure to insect stings. In the above case angioedema started after 5 hours of exposure without pruritus and urticarial rash suggesting non allergic etiology due to excess bradykinin release. The close differential diagnosis is C1 esterase inhibitor deficiency, either hereditary or acquired, causing angioedema. This was ruled out in the above case by normal C1 esterase inhibitor level. The etiology of red ants’ ingestion was concluded also on the basis of recurrent presentation on exposure to the same.

1. Havaldar PV, Patil SS, Phadnis C. Anaphylaxis due to red fire ant bite. Indian Pediatr. 2012; 49:237-8.

2. Freeman TM. Hypersensitivity to hymenoptera stings. N Engl J Med. 2004;351;1978-84.

3. DeShaze RD, Butcher BT, Banks WA. Reactions to the stings of imported fire ant. N Engl J Med. 1990;323:462-6.

4. Goddard J, Jarratt J, de Castro FR. Evolution of the fire ant lesion. JAMA. 2000;284:2162-3.