A woman in Arizona suffered an itchy red rash after a caterpillar fell on her shoulder – where her skin was exposed.
Although caterpillars are usually harmless, the 42-year-old woman experienced a stinging sensation after a fuzzy caterpillar fell on her left shoulder. A few minutes after the incident occurred her skin broke out in hives, also referred to as urticaria – a type of skin rash characterised by red, itchy bumps.
In the case report – published October 28 in the New England Journal of Medicine – it was stated that the caterpillar was a Hemileuca tricolor, or tricolor buckmoth caterpillar.
Not knowing the exact causes of the skin reaction, the woman called the Arizona Poison and Drug Information Center and also sent the photos she took of her skin rash to the Arizona Center.
Dr. Daniel Brillhart, co-author of the case report and an emergency medicine physician at Darnall Army Medical Center in Fort Hood, Texas, looked at the woman’s photos, and found that she experienced an allergic reaction to a toxic substance found on the hairs of the caterpillar.
The immune system usually reacts to these toxins when they touch the skin, and in most people that results in hives, Dr. Brillhart said. Chances are that if a caterpillar falls on someone’s the skin it will cause more rashes, than if were to just crawl on the skin.
According to Dr. Brillhart, the skin on a person’s back is much thinner than the one on the hands or legs, which is why the woman may have experienced a more severe reaction to the caterpillar’s toxin-coated hairs.
When tricolor buckmoth caterpillar hairs reach a person’s eye, they may cause conjunctivitis, commonly known as pink eye. Also if the hairs reach the lungs, the person may have difficulty breathing, Dr. Brillhart said.
“[They may cause allergic reactions but] caterpillars do not bite. Their mouths are not designed to pierce the skin,” Dr. Brillhart explained.
Although most caterpillars are not dangerous, it is important to know that the fuzzier they are, the more likely they are to cause allergic reactions.
The woman’s irritated skin cleared up in just a few days, after she followed a treatment that required her to apply antihistamine cream on her rash (aka caterpillar dermatitis).
Image Source: discoverlife