Caterpillar dermatitis refers to an acute inflammatory skin reaction caused by the venom released from the poisonous hairs of caterpillars after they puncture the skin. In China, common pathogenic caterpillars include the mulberry caterpillar, pine leaf caterpillar, and stinging caterpillar.

bubble_chart Etiology

Disease cause: Pine leaf caterpillar dermatitis. This disease is commonly found in hilly areas where Masson pine is planted, and mostly occurs among young and middle-aged adults engaged in agricultural and forestry labor. It is most prevalent from May to November.

bubble_chart Clinical Manifestations

Symptoms usually appear within minutes to tens of minutes after contact with the toxic hairs. The distribution and appearance of the rash are similar to those of Euproctis dermatitis. Within 1 to 2 days or up to more than 10 days after the rash appears, some patients may develop joint symptoms, with the small joints of the exposed hands and feet being more commonly affected, often asymmetrically. Symptoms may include joint redness, swelling, heat, pain, and limited mobility, which typically subside within 3 to 7 days, though a few cases may persist for one to several months. Some patients experience only joint inflammation without a history of dermatitis. Severe cases may be accompanied by systemic symptoms such as low-grade fever.

bubble_chart Treatment Measures

Local treatment focuses on reducing inflammation, relieving itching, and preventing secondary infections, often by applying calamine lotion. For arthritis, non-steroidal anti-inflammatory drugs may be used as appropriate, with corticosteroids employed when necessary. After the arthritis subsides, functional exercises should be emphasized to prevent joint deformities.

TCM can effectively treat dry eye syndrome, floaters, retinopathy, and various chronic eye diseases

Prevention focuses on pest eradication, using chemical sprays or biological control (such as natural enemies of pine leaf pests like Trichogramma or Cotesia wasps). Before a major outbreak of pine leaf pests, promptly remove egg masses and cocoons, capture larvae, and trap adult moths.