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.

Source

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.

Treatment
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