Anaphylaxis reaction to Samsum ant (Pachycondyla sennaarensis): a case series study

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Authors Information

1Department of Allergy and Clinical Immunology, Rasool-E-Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
2Department of Radiology, Ronald Reagan-University of California, Los Angeles Medical Center, David Geffen School of Medicine at UCLA, Los Angeles (CA), U.S.A.
3Department of Pediatrics, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
4Division of Allergy and Clinical Immunology, Department of Pediatrics, Bahrami Hospital, Tehran University of Medical Sciences, Tehran, Iran


Published: 11 February 2022
Accepted: 07 February 2022
Received: 24 November 2021


Background. Anaphylaxis is a life-threatening hypersensitivity reaction. The present study aimed to investigate the cases of anaphylaxis to ant stings in Iran to determine the characteristics of patients, geographical distribution and the type of ants that cause anaphylaxis. Methods. Patients with a history of anaphylaxis to ant sting underwent skin allergy test with extracted substance from Solenopsis invicta. Samples of ants were collected from the sites where each patient was bitten and their species were identified by a medical entomologist. Results. Nineteen patients (mean age: 26.2 years; range: 4-48 years) were included in the study. Most patients (89.5 percent) were female. The lower limb was the most common site of the sting and most stings had occurred in the morning (31.6 %) and evening (31.6%). Skin manifestations were the most common clinical symptoms (94.7%). Most cases of stings were observed in the Hormozgan province (89.5%) located in southern Iran. Sixteen patients had positive skin prick test for ant venom. All collected ants that caused anaphylaxis belonged to the Pachycondyla sennaarensis species. Conclusions. Ant sting anaphylaxis is not uncommon in Iran, especially in its southern regions. All cases of anaphylaxis in this study were due to Samsum ant sting (Pachycondyla sennaarensis), which is a species similar to the fire ant (Solenopsis invicta). Allergy skin testing with fire ant extract was positive and helpful in identifying samsum ant allergy in all cases.

Anaphylaxis; ant venoms; insects allergy; hypersensitivity; insect bites and stings.

Table of Content: Vol. 55 (No. 2) 2023 March

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