Purpose: Hairs from the caterpillar of the pine processionary moth, Thaumetopoea pityocampa, located in the pine forests of southern Europe and elsewhere, can become embedded in the cornea and conjunctiva. Disorders produced by the urticating hairs can be classified into a broad spectrum of severity from mild keratoconjunctivitis to anaphylactic shock. This report presents 3 cases that illustrate the range of corneal responses to embedded hairs of the processionary moth caterpillar.
Methods: Case series and review of the literature.
Results: A 51-year-old man (case 1), a 46-year-old woman (case 2), and a 67-year-old man (case 3) presented different manifestations as a result of contact with pine processionary caterpillar hairs. Case 1 had acute keratitis with decreased vision. He was treated with a corneal depot steroid 4 times daily for 3 months. After 4 months, he was asymptomatic. Case 2 had acute keratitis without vision symptoms. She was released without treatment, and 1 month later was asymptomatic. Case 3 experienced dry gritty sensations, probably because of blepharitis, but also presented asymptomatic caterpillar hairs embedded in the corneal stroma. He was instructed regarding lid hygiene for his blepharitis, and after 3 months the embedded caterpillar hairs had disappeared.
Conclusions: The most common ocular presentation of embedded hairs from the pine processionary moth caterpillar is keratitis. The urticating hairs can cause corneal infiltrates that disappear progressively over time. Steroid eye drops accelerate the resorption of these infiltrates.