Ocular lesions produced by pine processionary caterpillar setae (Thaumetopoea pityocampa) in dogs: a descriptive...

To describe, for the first time in dogs, the ocular lesions induced by the pine processionary caterpillar (PPC) setae, and the associated corneal histopathology, medical treatment, and outcome.

One hundred and forty client-owned dogs from Spain were studied. One hundred and twenty dogs came from the central area of Spain, 13 from the southern area, six from the northern area, and one dog came from the Mediterranean area.

Medical records from four veterinary ophthalmology practices were reviewed. Dogs that were presented from endemic areas and that had PPC setae identified during their ophthalmic examination were included in the study.

The following ocular lesions were identified: keratitis with crescent- or circular-shaped white stromal cellular infiltrates (98.57% [n = 138]), anterior uveitis (78.57% [n = 110]), conjunctival hyperemia and chemosis (33.57% [n = 47]), blepharitis (8.57% [n = 12]), and corneal ulcers (2.86% [n = 4]). Removal of the hairs by saline hydropulsion and medical treatment was successful in 99.29% (n = 139) of the cases. A single case healed following additional corneal reconstructive surgery to remove the deep corneal lesion and subsequent histopathology revealed an acute lesion with necrotic neutrophilic infiltrate and corneal edema. All ocular lesions resolved completely within 15 and 30 days after presentation, with the exception of one case that developed endophthalmitis.

Pine processionary caterpillar should be included in the differential diagnosis of acute ocular lesions, especially if keratitis with corneal cellular infiltrate and anterior uveitis are present, in dogs from endemic areas during the months of spring and summer. In the majority of cases, irrigation and removal of the hairs together with medical treatment leads to a good outcome.