Introduction
Blister beetle dermatitis is the condition caused due to the contact of beetle over the human skin. The condition is not because of its bite. It is a type of contact dermatitis. The causative factor is the chemical component present on the surface of the insect. When the beetles come and sit on the surface of the human skin, our skin will react to it, causing blisters. This is also known as” paederus dermatitis” or “dermatitis linearis”.
Other synonyms: "pederus dermatitis” or “dermatitis linearis”.
What Is Blister Beetle Dermatitis?
Blister beetle dermatitis or “Paederus dermatitis” is a cutaneous condition, a type of contact dermatitis that is peculiar. It is caused by a beetle that belongs to the genus called paederus. The condition is characterized as a red raised blister or welt that contains fluid or pus. Usually, such rove beetles do not bite humans; the condition only occurs accidentally. Accidental contact on farms or crushing of beetles by humans can cause blister beetle dermatitis. In detail, the beetles secrete a chemical component called paederin. paederin is a vesicle-causing component. Beetles in contact release paederin that provokes skin, causing blisters and various skin problems. The paederin is produced high in female beetles.
Which Type of Beetle Causes Blister Beetle Dermatitis?
Beetle or rove beetles, belonging to the genus paederus and the order Coleoptera in the Staphylinidae family, is the causative insect. Such beetles are distributed all over the continent but not in Antarctica. In parts of South America, such beetles are called by various names: pito, poto, podo, and Bicho de Fuego. Blister beetle dermatitis is prevalent in central Africa, the south part of Turkey, Okinawa, and India.
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Causative Organism: Rove beetles.
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Order of Species: Coleoptera.
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Genus: paederus.
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Family: Meloidae.
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Causative agent: Paederin.
Beetles causing dermatitis have the head in black color, thorax in red color, an upper and lower abdomen, and wings. When it comes to the beetle size, the adult beetles usually range from 7 millimter to 10 millimeters in length and 0.5 millimter to 1 millimeter wide. They live in moist areas and are usually seen on farming land. It is attracted to light.
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Head: Black.
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Thorax: Red.
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Size: 7 mm to 10mm length and 0.5 mm to 1mm wide.
What Happens After Beetle Contact?
The human body shows various responses in the skin after comig in contact with beetles. The skin reactions may vary with certain factors such as the amount of concentration of paederin, exposure duration, and the allergic response of the individual. Blisters are seen within 24 hours after contact with beetles. Initially, a slight red swollen area is seen, which lasts for two days. Vesicles and bullae are present in moderate cases, and the blisters will dry within a week. During the desquamative stage, it leaves a hypopigmented patch. The scar is usually not seen. In severe conditions, the individual will experience various symptoms, such as fever, vomiting, neural pain, and arthralgia.
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Mild symptoms - Swollen reddish area lasts for two days.
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Moderate symptoms - Vesicles and bullae for weeks.
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Severe symptoms - In addition to mild, and moderate symptoms, fever, vomiting, neuralgia, and arthralgia.
Are Beetles Dangerous?
Although blister beetles do not show any permanent complication, pain is the major discomfort experienced by humans. The spread of cantharidin in various parts of the human body, such as the eyes, genitals, arms, and neck, will cause major discomfort. It is also important to avoid secondary infections as well. When the cantharidin contacts the surface of the eyes, it is referred to as the “Nairobi eye.”
Is This a Seasonal Infection?
It is not a seasonal infection, but the climate has a prominent role in the beetles' activity. As we know, beetles are likely seen in moist areas; they are very active in rainy seasons and less active in summer. Rainy seasons and wet conditions favor the activity and dispersal of beetles in a faster range.
What are Areas At Risk of Exposure?
Paederus type of beetles is mostly present in crop fields to eat the pests in the plants. They have also been seen in flowering plants and also in riverbanks. By attracting light considering its prey, it migrates to houses, hostels, and other human-populated areas. It is also seen in harvested products and processed areas. Urbanization is also a factor. Nighttime contact is also common because beetles are attracted to artificial indoor light.
What Is the Clinical Feature of Blister Beetle Dermatitis?
Blisters are commonly seen on the face, neck, forearms, and in regions of the trunk. In the case of kissing lesions in which the affected area is in contact with another skin region, it is seen in the armpit, backside of ears, and elbow crook. Delicate skin surrounding genitals and eyes or direct contact with eyes can also occur. Symptoms during the onset of infection are intense burning, painful itching, and stinging sensation. It is an inflammatory condition the three major symptoms such as redness, pain, and swelling, are obvious. The infected area is erythematous with the presence of vesicles, subcorneal pustules, and bullae. In the Nairobi eye, conjunctivitis is the inflammation of the conjunctiva, and epiphora refers to the excessive watering of the eyes.
What Is the Treatment for Blister Beetle Dermatitis?
Usually, blister beetle dermatitis will heal on its own in mild cases. Topical treatment is advised in severe cases associated with systemic involvement of blister beetle dermatitis.
Some of the treatment measures are mentioned below.
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It is important to wash hands with soap and water as soon as possible after contact with beetles.
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In extreme cases, intravenous injection of steroids is useful.
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The lotion is advisable to soothe itching.
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Application of artificial eye drops in Nairobi eye.
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Application of antihistamine.
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Nonsteroidal anti-inflammatory drugs (NSAIDs) in severe cases and analgesics to reduce pain and fever.
Many methods can prevent blister beetle dermatitis. Prevention is made to avoid the risk of blister beetle dermatitis and other complications. Several nonmedical management is done to prevent blister beetle dermatitis.
Some of the nonmedical preventive measures for blister beetle dermatitis are given below.
- Brushing or blowing off the beetle instead of handling it with direct hands.
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Avoid sitting directly under lights at night.
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Closing doors and windows during nighttime.
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Wear long-sleeve pants and long-sleeve shirts while gardening.
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Housing modifications.
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Use net drapes to avoid contact with beetles.
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Use of pesticides in targeted areas.
Conclusion
Blister beetle dermatitis is not a life-threatening condition to be worried about. Proper awareness of this infection is mandatory. Detailed history taking and patient examination is important to avoid misdiagnosis. Awareness among healthy individuals will lead to correct diagnosis and effective treatment. Prevention is Better than cure.
