Imported fire ant envenomation: A clinicopathologic study of a recognizable form of arthropod assault reaction

Gabriel Villada, Farhaan Hafeez, Jose Ollague, Carlos H. Nousari, George Elgart

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Background: Skin reactions to the sting of the imported fire ant have characteristic clinicopathological features. Methods: One case of experimental envenomation was prospectively followed during 48 hours, with biopsies. In addition, 6 cases from our laboratory were retrospectively evaluated histopathologically for the following features: spongiosis, exocytosis (and type of cells), pustule formation, erosion/ulceration, epidermal necrosis, scale/crust, papillary dermal edema, inflammatory dermal infiltrate (cell type, density, depth, distribution, shape), red blood cell extravasation, vasculopathy and vasculitis. Results: The typical lesion follows a very distinctive clinical and histopathologic evolution over 48 hours, with the formation of a subepidermal pustule overlying a wedge-shaped area of dermal collagen basophilic degeneration with scattered neutrophils. In the 6 cases retrieved from our files, the main features were a superficial and deep dermal, perivascular, periadnexal and interstitial infiltrate consisting of neutrophils, with basophilic degeneration of the collagen. A subepidermal pustule was noted in half of the cases. Conclusions: In biopsies taken in a clinical setting, even in the absence of the characteristic subepidermal pustule, the diagnosis of imported fire ant sting can be suspected if there is a superficial and deep perivascular, periadnexal and interstitial infiltrate composed of neutrophils, with some basophilic denaturation of collagen.

Original languageEnglish (US)
JournalJournal of Cutaneous Pathology
StateAccepted/In press - 2017


  • Arthropod assault
  • Basophilic collagen degeneration
  • Imported fire ant
  • Subepidermal pustule

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Dermatology


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