Inflammation and Hives from Kemushi (Caterpillars)

kemushi caterpillarIf you have curious kids who love bugs then tell them to stay away from this one, the hairy caterpillar/kemushi. Take care to avoid these “hairy” caterpillars as they have developed hairs or sharp spines that are capable of transmitting various toxins causing inflammation and hives on the skin. In most cases direct contact with the insect is necessary to provoke a reaction. However, the irritating hairs can also be detached and can go airborne adhering to skin or clothing causing a rash.

kemushi caterpillarI found myself with an irritating rash on my neck and arm last year, and hadn`t been anywhere near a caterpillar. My dermatologist said the caterpillar hairs could have blown onto my skin, as he had seen this in many cases.

If you find yourself or your child with a rash or hives please consult with your dermatologist. It might be a reaction from kemushi (hairy caterpillars) and can be easily treatable.

Symptoms: Redness, rash, itchiness, small red bumps and pain. 

Treatment: Remove the caterpillar hairs with tweezers or sticky tape. Wash the area with soap and water. Keep the area cool. Clothing should be removed and laundered thoroughly.

Contact a dermatologist. They will prescribe topical steroids or oral antihistamines to treat the inflammation and irritation.

Usual Length of Treatment: Depends on how severe the condition is and the prescription strength – usually one to two weeks. Strong topical steroids are normally not used for more than one week.

kemushi caterpillar

kemushi caterpillarTypes of Hairy Caterpillars:
Tussock moth (ドクが): Feeds on Sakura, Ume, Roses & Japanese Knotweed
Peak Season: May & June

Tea Tussok Moth/Japanese Browntail Moth (チャドクガ): Feeds on Japanese Camellia
Peak Season: May, August & September

Yellow-tail, Goldtail Moth or Swan Moth (モンシロどクガ): Feeds on Sakura, Ume, Apple, Chestnut, Oak and Mulberry Trees
Peak Season: May, July & September

If you need medical attention in English, visit our English speaking doctors page. You can also call the 24 hour doctor referral service at Himawari.

P.S. Visit our health related posts

Six Common Children’s Skin Rashes in Japan – Heat, Virus or Bug?

Five Common Contagious Children’s Skin Ailments in Japan – What is it? How to cure?

Common Illnesses and Terms Among Young Children in Japan

English Speaking Tokyo Dermatologists

Tokyo English Speaking Pediatricians

Tokyo English Speaking Doctors


Inflammation and Hives from Kemushi (Caterpillars)


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