P‐29 Pustular dermatosis caused by fire ant (Solenopsis invicta) stings in a dog

Abstract

Solenopsis invicta (lavapés ants or imported fire ants) are insects that belong to the Hymenoptera order and Formicoidea superfamily. Native to Brazil, this aggressive ant species is today disseminated throughout the Americas. In humans, the sting of the fire ant causes an urticarial papule that progresses within 24 h to a highly pruritic, sterile pustular dermatitis. Children and alcoholics are more often affected, presenting with massive injuries. Subcorneal neutrophilic pustular dermatitis is the usual histopathological finding. One study has reported that fire ant stings in dogs leads to a vertically oriented necrotizing dermatitis with collagen degeneration. This abstract reports a natural fire ant‐induced dermatosis in a dog. We report a female, intact, young‐adult, mixed‐breed dog presented for routine check‐up. Physical examination revealed several grouped, nonfollicular, circumscribed abdominal and inguinal pustules. The pustules were relatively tense, circumscribed by a slight erythematous halo, and several dead fire ants were attached to the skin and hairs. No bacteria were seen on cytological examination. Histopathological examination revealed an intraepidermal neutrophilic pustule and dense dermal interstitial, predominantly neutrophilic, infiltration, which extended to the panniculus. Collagen degeneration and edema were also observed. This case documents that fire ant stings can produce pustular intraepidermal dermatitis in dogs similar to that observed in humans. Funding: Self‐funded.