Definition

Venenata dermatitis is an inflammatory reaction that occurs on the skin due to contact with fluids or insect body parts. The insect most often causes dermatitis venenata is the Paederus fuscipes beetle, known as the tomcat, because it is similar to the United States fighter plane with the same name. Apart from dermatitis venenata, this condition is called dermatitis paederus (because the most common cause is the Paederus beetle) and dermatitis linearis (because the resulting wounds are generally line-shaped). Venenous dermatitis is included in the large group of contact dermatitis, namely inflammation of the skin that occurs due to contact with an object or substance. In this case, dermatitis occurs due to contact with substances produced by insects.

Causes

Venenata dermatitis is caused by the pederin compound produced by the Paederus beetle. The pederin compound is a weak acid and is found in all life phases and all parts of the beetle's body, except the wings. This compound is only produced by female beetles, and has a weak antibacterial effect, but is highly capable of poisoning human cells. Pederin is more toxic than the black widow spider's venom, which is 15 times more potent than cobra venom. In fact, this compound is not damaged when boiled in hot water. The poisonous power of pederin can last up to 10 months and dried Paederus beetles remain poisonous for up to 8 years.

The pederin compound usually comes into contact with the skin due to the insect's pressure reflex when it touches the skin. This compound is released by the beetle's hemolymph (a kind of blood in humans), which comes out when the insect is pressed. Pederin damages DNA (deoxyribonucleic acid) in cells. Furthermore, DNA damage causes the death of skin cells. However, this skin cell death mainly occurs in the outermost layer of the skin.

Risk factor

Dermatitis venenata is found throughout the world except Antarctica, mainly in tropical and subtropical areas. Usually, outbreaks occur in southern Europe and Asia, and in other parts of the world, especially in the lowlands. Dermatitis venenata can attack anytime, but outbreaks usually occur during the rainy season. The spread of Paederus insects generally occurs during the harvest season because, at that time, the amount of food decreases. This beetle is a predator of pests such as other insects, moths, tadpoles, and worms, so when the number of pests decreases, this beetle will move to populated areas.

This beetle has phototactic properties or approaches light, especially ultraviolet and white light. At night, these beetles can be found gathering near light sources such as lamps in areas with lots of wood or urban areas. Therefore, humans are usually exposed to these insects at night.

Symptoms

Venenata dermatitis can occur in anyone. Patients are often unaware of contact with insects, because the contact occurs while the patient is sleeping accompanied by a reflex to suppress the insect. Wounds are usually noticed in the morning. However, this injury does not occur directly; there is a latent period which is the time between exposure to pederin and the appearance of the wound. Typically, sores appear within 24-48 hours of contact with the insect.

The initial wound is reddish in the form of lines (railroad pattern, train tracks), which occurs as a result of pressing the insect and the movement of "smearing" the surrounding skin with the poison. Furthermore, elasticity, skin crusts and peeling of the skin may appear. Wounds that are reddish can disappear after 2 days, but if elasticity, crusting and peeling of the skin occurs, the wound usually takes 7-8 days. The scar is usually a line that is darker than the skin, which disappears within 1 month. In severe cases, fever, joint pain, nerve pain, runny nose and inflammation of the eardrum can occur.

Apart from that, kissing lesions can also occur, which occur due to the meeting of one part of the body with another part of the body. For example, this skin disorder can occur on the upper and lower arms because when sleeping, the two parts of the arm touch each other. Another form of injury can be a reddish plaque accompanied by erosion of the skin.

Pederin can move through sheets or clothes, so it can attack several parts of the body at the same time. The parts of the body most often attacked are the face, neck, and arms.

Diagnosis

The diagnosis of venous dermatitis can be made by considering the history of the disease and the form of the wound. The history required to reach a diagnosis of dermatitis venenata is the presence of wounds on the skin accompanied by itching and burning sensations, a history of contact with Paederus beetles, or the patient coming from an endemic area (an area with many similar cases). The skin disorders that appear also have a distinctive appearance.

Management

Venenous dermatitis generally heals on its own. If this dermatitis is managed, the management is similar to other contact dermatitis. If the patient has just had contact with insects, treatment can be carried out in the following way:

• The affected area is cleaned with soap and water
• Antiseptic tinctures of iodine applied topically can neutralize pederin
• Administering itching medication

This therapy can reduce the severity and prevent further complications of venous dermatitis. If itching and burning appear, calamine or sulfadiazine can be given to the affected area to cool and reduce the itching.

If a wound on the skin has appeared, the doctor can administer topical anti-inflammatory medication in the form of an ointment. This anti-inflammatory drug can be applied daily until signs of recovery appear, usually within 7-10 days. Antibiotics may also be necessary. Usually, the antibiotics given are oral antibiotics. If nerve pain is present, the doctor may prescribe special medications that can help relieve nerve pain.

Complications

Complications typically arise from direct exposure to pederin and secondary infections. Secondary infections are bacterial infections that develop subsequent to the original skin lesion or infection. Patients may exhibit hyperpigmented scars that may take quite a bit of time to resolve fully. Severe complications may arise, such as the appearance of ulcers and significant skin peeling, which could require patients to receive inpatient treatment.

Prevention

Preventing Paederus beetle bites necessitates collaborative efforts among governmental bodies, medical facilities, and local residents. The process might include the following steps:

1. Minimize the bug population in the environment

This can be accomplished by increasing public awareness of the habitats of insects, their affinity for light, and strategies to manage contact with the insects. The act of raising awareness might be done, especially during the rainy season. The use of deltamethrin has the potential to reduce insect populations in proximity to residential areas, particularly if the residential areas are close to the paddy fields. In addition to pyrethroids and malathion, alternative pesticides can also be used. 

2. Steer clear of insects coming into contact with your skin

This can be accomplished with the following methods: close the windows prior to turning on lights at night; use mesh vents to allow airflow while preventing insect entry; avoid falling asleep in close proximity to lights; spray insect killer in the rooms; and use insect traps that emit ultraviolet light. You can also use insect-repellent creams and wear long clothing, gloves, or glasses when you work at night.

3. Reduce the amount of fluid the bug releases after it comes into contact with the skin

You can accomplish this by flicking or blowing the beetle without crushing it. Another option is to delicately pick up the bug using paper or other materials, making sure it is not damaged.

4. Avoid or lessen the development of skin lesions after skin contact

It's best not to scratch open sores. In case the beetle gets inadvertently squeezed, make sure to cleanse the impacted area using soap and water to eliminate the pederin as much as possible. After that, you could apply calamine or a cold compress to the skin. 

When to see a doctor?

If you notice blisters or reddish plaques accompanied by a burning and itching sensation, it's important to seek medical attention. A doctor can prescribe topical medications to reduce inflammation and antihistamines to relieve itching. They can also provide information on how to heal your skin lesions. If you experience symptoms such as fever, joint pain, nerve pain, or excessive skin peeling, it's important to seek medical assistance promptly.

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