Saturday, February 04, 2006

Paederus Dermatitis

Link to my main Paederus Dermatitis/ Rove Beetle Posting

“Nairobi eye” is one of several conditions that can arise when beetles of the genus Paederus (Coleoptera: Staphylinidae) are crushed against exposed skin. This causes the release of the chemical pederin, a toxic amide found in the haemolymph of Paederus beetles. Unless immediately washed off the skin with soap and water, or flushed from the periorbital area with water, the deposited pederin can lead to “linear” dermatitis or more severe symptoms. Pederin on hands and clothing/bedclothes can be transferred to and cause dermatitis in other areas (e.g., genitals and periorbital area), though the dermatitis itself is not transferable.

History of disease: Extracts from Paederus beetles have long been known to be toxic, and also have enjoyed a long history of use in herbal medicine. For example, the Chinese (A.D. 739) recognized that compounds from Paederus could cause skin to swell and peel, and used Paederus extracts to treat boils, nasal polypi, and ring worm1. In recent years, Paederus beetles have been associated with outbreaks of dermatitis in various areas, including Africa, Asia and South America.


Blister Beatle Again

I've been seeing a lot of this in Penang. Blisters on the skin caused by the Cantharidin toxin in Blister Beetles. Mainly in the houses and flats near the hills. Here are some useful info I read .

Previously I thought that many of these cases were due to Blister Beetles, but I have realised that through my patient's descriptions, that these cases were more likely to be due to the Paederus Beetles which are smaller. However both cause quite similar burns. Here is some information on Blister Beetles.

Blister Beetle Info

"Many blister beetles contain a specific bicyclic monoterpenoid, cantharidin (C10H12O4) (Gr. "kantharis" or beetle). A related substance, anemonin, is found in certain plants (Ranunculaceae). Cantharidin is not soluble in water, but is fat-soluble. Cantharidin binds chemically to phosphatases 1 and 2A. These enzymes play a role in cell proliferation, membrane channels and receptors, modulation of protein kinases and modulation of other phosphatases. The toxin is very stable. Dead beetles are still dangerous. Consequently control by means of insecticides does not remove the danger. The toxin protects the beetles from predators and is found in the haemolymph and gonads. A beetle contains 1-5% cantharidin by dry weight. Males contain more toxin than females. A male beetle transfers cantharidin to a female during copulation ("nuptial gift"). This is then passed on with the eggs so that these too are protected against predators.

On skin contact with cantharidin-containing blister beetles, local tissue irritation occurs after a few hours. This results from the disruption of tonofilaments in the desmosomes with acantholysis and intra-epidermal blister formation. Redness, oedema and vesicles can appear on the skin. Sometimes there are "kissing lesions" on the elbow or in the hollow of the knee.

For external lesions, the skin should be rinsed copiously as rapidly as possible. After disinfection, silver sulphadiazine cream should be applied. Subsequent care is the same as for a burn. Skin lesions caused by cantharidin practically always heal without leaving scars. An eye that is affected should be rinsed copiously. Afterwards an antibiotic- and steroid-containing eye ointment should be applied."

Rove Beetle Dermatitis
Originally uploaded by DrChan.

More Paederus Dermatitis Pics

Y Shaped Kissing Lesion

Paederus Dermatitis on Face

Paederus Dermatitis on Armpit

Paederus Dermatitis on Neck

Paederus Dermatitis on Arm


At 1:19 PM, Blogger Jere said...

I recently came back from a medical mission trip to the Amazon region of Brazil. 3 of the 11 on our trip came down with paederus dermatitis, exactly as you describe. The locals called this bug the 'poto' bug. Thanks for your info, especailly the photos!

By the way, your link on your menu for paederus dermatitis doesn't work. I found your page through Google.

At 5:14 AM, Blogger TrueBluePenangite said...

Just as an aside, the dermatologist that I used to do clinicals with uses cantharidin drops to get rid of hard to kill warts. It really works better than liquid nitrogen and does not leave a scar.

At 5:53 PM, Anonymous Anonymous said...

Hi, I was diagnosed as well paederus hermatitis;I stayed in Penang, Bayan Lepas - not really hillside actually seaside & caught unaware when it happens. Scratched the itchy place around 4 days ago, but get worse since yesterday. I went to doctor, & it seems like I am having a severe burns & secondary infection on my armpit with bacterium & viral come into place.May I know is this the same with the those staying near to the oil palm plantation who get stung with a kind of insect as well? Another question would be is it normal to have many small bubble-like boils with harden, red swollen skin up at the armpit area? It is all small, concentrated & tiny bubble-like boils across the armpit area.

At 3:33 PM, Blogger Paula said...

I've lived in Tanzania for the past 15 years and we have the Nairobi Fly. The burn doesn't start until hours later so it's hard to know when you made contact. The best treatment....toothpaste. The baking soda in it neutralizes the acid. It's important to put the toothpaste on when the site is like a first degree burn before it starts to blister.

At 11:38 PM, Anonymous stacey said...

I just found out I have 'Nairobi eye', also acquired in Tanzania (Dar). At first the doctor thought it was ocular herpes; apparently the two look very similar and are sometimes confused.

At 4:19 AM, Anonymous Anonymous said...

Hi, I am searching in the internet for some skin disease because I have been beaten (as far as i know) by this Nairobi fly and I stumble this page. It happened about 4 days ago and now it is as big as quarter dollar coin and look the same as the photo. Could anybody please tell me the medicine i could use, its getting bigger and I am getting nervous about this.. I am in Ghana right now and medicine here are scare.. any suggestion will be greatly appreciated.. thank you...

ps forvige my English..


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