Pine processionary caterpillar as a new cause of immunologic contact urticaria

Abstract

Nowadays, caterpillars are included among the agents that elicit contact urticaria by a non-immunologic mechanism. Our objective was to find the rôle that an IgE-mediated mechanism could have among patients with suspected contact urticaria from pine processionary caterpillars. 16 patients with suspected contact urticaria from this caterpillar were studied by prick testing and specific IgE detection by immunoblotting. 87% of the patients had a positive prick test and immunoblotting for caterpillar extract. In these allergic patients, the symptoms associated with urticaria were: angioedema (79%), conjunctivitis (36%) and severe anaphylaxis (14%). The most frequent localizations of the wheals were the neck (100%) and forearms (93%). Angioedema was more frequent on the eyelids (79%). The IgE-immunoblot detected in the caterpillar extract several reactive bands, with apparent MWs from to 45 to 4kDa. A total of 5 major allergens were identified, but a band around 14kDa proved to be the dominant allergen. Sensitization to Thaumetopoea pityocampa was found to be the most important mechanism of airborne contact urticaria from this caterpillar. Low-MW proteins are the main IgE binding components of crude caterpillar extract.

Caterpillar Dermatitis in Two Siblings due to the Larvae of <i>Thaumetopoea processionea</i> L., the Oak Processionary Caterpillar

“…It was shown that this protein activates mast cells via a direct non-immunological effect (non-IgE-mediated mediator release) and a type I allergic hypersensitivity reaction (IgE-mediated mediator release) [12]. The existence of a (true) type I allergic hypersensitivity reaction to the larval extracts of the pine processionary caterpillar [12, 13, 14]and the oak processionary caterpillar [12]was confirmed by positive skin prick tests and the determination of specific IgE antibodies. Mechanical irritation from penetration of the setae (foreign body reaction) appears to be a third mechanism which is responsible for the reactions in skin and mucous membranes [10, 11, 12, 13, 14].…”

Reacções Cutâneas, Oculares e Respiratórias pela Processionária (Thaumetopoea Pityocampa)

“…12,14,15 7. CONCLUSIONS Pine processionary cutaneous reactions are common in the human population of South Europe where pine processionary moth is endemic.…”

“…The lesions appear within hours and they can persist for several days. In contact urticaria, there are evanescent itchy papules, often in association with angioedema, particularly on the eyelids 14 and mucosae. 18 Linear and figurated papulo-urticarial lesions are seen in children who let caterpillar stroll on their skin.…”

“…The occupations at greater risk are pine cone collectors and lumberjacks, followed at some distance by resin collectors, farmers, forest wardens, gardeners, bricklayers, and haulage contractors who work in regions of pine forest. [11][12][13][14] Children are another risk group, most likely because their natural curiosity leads them to touch the caterpillars or play with sand or vegetation that has these larvae. 15,16 Symptoms may occur with the start of the pruning season and pine cone collection in the fall, or wood and sand collection in summer months.…”

Outbreak Report of Airborne Caterpillar Dermatitis in a Kindergarten

“…4). Other signs are conjunctivitis, pharyngitis, malaise and upper respiratory tract symptoms including respiratory distress [1,2,3,8,9,10,11,12,13,14,15]. Few cases of life-threatening anaphylactic reactions have been reported [4, 5].…”