INSECT BITE REACTIONS

Insect bites can cause discomfort and concern. In severe cases, they may even require urgent medical attention. The symptoms and appearance of insect bites can vary widely, allowing for identification based on the pattern of skin lesions in many cases.

What is the difference between insect bite and sting?

The main difference between an insect bite and sting lies in how the insect delivers its harmful substance to a person or animal:

• Insect Bite:This occurs when an insect, such as a mosquito, bedbug, or tick, pierces the skin to feed on blood or tissue fluids. The bite typically results in a small, red, itchy bump or welt at the site of the bite. Insects that bite do not inject venom or other substances into the skin.
• Insect Sting:This happens when an insect, like a bee, wasp, hornet, or ant, uses its stinger to inject venom into the skin. Stings often result in immediate pain, redness, swelling, and sometimes itching or a burning sensation. The venom can trigger an allergic reaction in some people, leading to more severe symptoms like difficulty breathing, swelling of the throat, or even anaphylaxis.

Common type of Insect Bite Reactions

Local reactions

Insect bites and stings are typically caused by an irritant substance found in the insect's saliva, leading to an inflammatory reaction at the site of the punctured skin. Initially, the affected area may appear red and itchy, with potential swelling developing over time. A single bite or sting mark is often visible, although dual marks can be observed with certain bites, such as from spiders or centipedes. Symptoms usually subside within a few hours, but some individuals may experience a delayed reaction, including blisters and tissue necrosis with certain bites. Immunocompromised individuals are at risk of developing severe local reactions and may require prompt medical attention.

• After an insect bite, it's important to wash the site with mild soap and water.
• Using an ice pack or cold compress can help reduce swelling and discomfort.
• Applying calamine lotion to the affected area can provide relief from itching.
• Taking antihistamines can help alleviate allergic reactions and itching.
• In cases of severe local reactions, oral steroids may be prescribed for inflammation control.

PapularUrticaria

This is a hypersensitivity reaction commonly triggered by mosquito, flea, or bed bug bites, often affecting young children (typically aged 2-10 years). Following an insect bite, it begins with itching and a red bump. This condition is characterized by recurrent, itchy bumps measuring 0.5-1 cm on exposed areas like the forearms, legs, face, and scalp. Patients may scratch these bumps, leading to larger bumps with surrounding pigmentation. Covered areas like the genitals, chest, thighs, and underarms are usually spared. New lesions can emerge in between existing ones and may reactivate older lesions. This condition can last for months to years.

Preventive measures such as wearing full-sleeved clothes, using insect repellents, and using mosquito nets during sleep can help avoid new lesions. For active episodes, it's advisable to seek guidance from a dermatologist for appropriate treatment.

Paederus Dermatitis or Blister Beetle Dermatitis

This is an irritant contact dermatitis caused by contact with a beetle. Beetles are active at night, so reactions often appear in the morning. Paederin, a potent blistering agent released by the beetle, is responsible for this reaction. Unlike a bite or sting, this reaction occurs due to contact with paederin. Symptoms typically develop around 24 hours after exposure and vary based on the concentration of paederin and the duration of contact.

In mild cases, there may be slight redness lasting for 2-3 days.Moderate cases exhibit redness with blisters that dry out, forming crusts and scales. This stage resolves with hyper or hypopigmentation but without scarring.Severe cases involve extensive blistering and may lead to systemic symptoms like fever, joint pain, and vomiting.

In some instances, the reaction sites can become infected, prolonging healing. Lesions near the eyes can even cause conjunctivitis.

Treatment involves washing the affected area promptly and avoiding scratching to prevent spreading. For moderate to severe cases, it's crucial to seek medical attention from a dermatologist.

SPECIFIC INSECT BITES

Mosquitoes bites

These are the most common reactions to insect bites:

• Localized reaction: This can include pain, itching, redness, and mild swelling or red bumps at the bite site. These symptoms typically resolve within 24-48 hours. In some cases, larger firm lesions may develop, requiring medical attention.
• Papular urticaria: This is a common reaction following mosquito bites, characterized by recurrent itchy bumps that can lead to larger bumps with surrounding pigmentation.
• Rare systemic allergic reactions: Although uncommon, systemic allergic reactions can occur after insect bites.
• Disease transmission: Mosquito bites can also transmit diseases, making prevention and protection important.

Ticks Bite

The primary concern associated with tick bites is disease transmission. Tick paralysis and allergic reactions are also potential manifestations. Among the most frequently reported tick-borne diseases in humans are Lyme borreliosis (Lyme disease), Rocky Mountain spotted fever (RMSF), human ehrlichiosis, and babesiosis.

Mite bite

Demodex infestations typically lead to red, itchy bumps on the skin, which can be solid or filled with pus. These lesions primarily appear on the face. In some cases, Demodex infestations can mimic symptoms of rosacea, and in severe instances, they may cause nodulocystic lesions.