From the Guidelines
Brown tail moth rash should be treated with oral antihistamines and analgesics to reduce itching and pain, and cold compresses can help reduce local pain and swelling, as there is no specific treatment for the rash itself, but rather management of its symptoms 1. To diagnose the rash, it is essential to consider the patient's history of exposure to the brown tail moth caterpillar and the presence of characteristic symptoms such as erythema, pruritus, and pain.
- The rash is caused by the toxic hairs of the brown tail moth caterpillar, which trigger a histamine response in human skin.
- Treatment options include:
- Oral antihistamines like diphenhydramine (Benadryl) 25-50mg every 6 hours or cetirizine (Zyrtec) 10mg once daily to reduce itching and inflammation.
- Analgesics to reduce pain.
- Cold compresses to reduce swelling and discomfort.
- Calamine lotion or hydrocortisone cream (1%) to reduce itching and inflammation.
- It is crucial to wash the affected area with soap and water to remove any remaining hairs and prevent further irritation.
- In severe cases, prescription-strength steroids may be necessary to manage the allergic reaction.
- The rash typically resolves within a few days to two weeks with proper treatment, but it is essential to avoid areas with known infestations during peak seasons to prevent re-exposure 1.
From the FDA Drug Label
Directions for itching of skin irritation, inflammation, and rashes: adults and children 2 years of age and older: apply to affected area not more than 3 to 4 times daily Purpose Anti-itch
The diagnosis of Erythema (skin redness) caused by Brown Tail Moth (Euproctis chrysorrhoea) caterpillar rash is not directly supported by the provided drug labels. However, for the treatment of skin irritation and rashes, hydrocortisone (TOP) can be applied to the affected area not more than 3 to 4 times daily for adults and children 2 years of age and older 2. For anti-itch purposes, hydrocortisone (TOP) can be used 2. Children under 2 years of age and children under 12 years of age should ask a doctor before using the medication 2.
From the Research
Diagnosis of Erythema caused by Brown Tail Moth Caterpillar Rash
- The diagnosis of erythema caused by Brown Tail Moth (Euproctis chrysorrhoea) caterpillar rash is based on the clinical presentation of erythematous and wheal-like skin lesions, which may gradually become more infiltrated and develop into erythematous papules or vesicles 3.
- The skin lesions are typically caused by the penetration of nettling hairs from the caterpillar into the skin, leading to damage and bulla formation of the surface epithelium and early inflammatory signs consisting of edematous changes of the dermis and pervascular infiltration of neutrophils, eosinophils, and mononuclear leucocytes 4.
Treatment of Erythema caused by Brown Tail Moth Caterpillar Rash
- The treatment of erythema caused by Brown Tail Moth caterpillar rash may involve the use of topical corticosteroids, although their use should be weighed against the potential risks and benefits, particularly in patients with suspected infections 5.
- Antihistamines, such as cetirizine, may also be used to relieve urticaria and other allergic symptoms, but their use should be monitored for potential side effects, such as drowsiness, and for the risk of cutaneous drug eruption 6, 7.
- In severe cases, immunosuppressive drugs, such as cyclophosphamide, may be considered, although their use should be carefully evaluated and monitored due to potential side effects 6.