OVERVIEW

Insect bites can be painful and scary. Sometimes it can be life threatening and person may need emergency treatment. Different insect bites can have different manifestations. By looking at pattern of skin lesions most of the time it can be identified easily.

CAUSES

What is the difference between insect bite and sting?

Common type of Insect Bite Reactions

Local reactions

It is caused by irritant substance concentrated in saliva of insect. Normally it is an inflammatory reaction at site of punctured skin. Affected site initially will be red and itching can be there, with time swelling may develop. Single bite/sting mark may be visible. Dual bite marks can be seen with spider bites and centipede envenomation. Symptoms subside in few hours sometimes local reaction can be followed by delayed reaction. Blisters and tissue necrosis can develop with spider and centipede bites.Immunocompromised patients may develop severe local reaction.
Treatment

• Site of insect bite should be washed with normal soap and water.
• Ice or cold pack can be used to reduce swelling.
• Calamine lotion can be applied.
• Antihistaminics
• For severe local reaction oral steroids can be used.

PapularUrticaria

It is a hypersensitivity reaction to insect bites. Most common insects are mosquitoes, fleas or bed bugs. It is more common in young children (typically 2-10 years).It after insect bite it starts with itching and red bump. It is characterized by recurrent itchy 0.5-1 cm bumps on exposed sites (forearm, legs, face, scalp) which may be scratched by patient and recurrent itching may lead large bump with surrounding pigmentation. Covered areas like genitals, chest, thighs, underarms are spared. New lesions can appear in between. New lesions can reactivate older lesions. It may last months to years.

To prevent new lesions protecting exposed body sites can help. Full sleeve cloths, insect repellants and mosquito nets during sleep should be used. To treat active episodes contact your dermatologist.

Paederus Dermatitis or Blister Beetle Dermatitis

It is an irritant contact dermatitis caused by a beetle. Beetles are nocturnal insects and most of reactions happen in night only, that’s why patient observes it in morning. This reaction developed due to paederin, a strong blistering agent released by beetle. There is no bite or sting in this reaction. Reaction usually develop about 24 hours after contact and depends on concentration of paederin and duration of exposure.

• In mild cases, there is slight redness lasting for 2-3 days.
• In moderate cases, redness with blisters which dry out with crusting and scaling. It resolves with hyper or hypopigmentation without scarring.
• In severe cases, more extensive blistering with systemic symptoms of fever, joint pain, vomiting.

Sometimes reaction lesions can be secondary infected and prolong healing. Near eye lesions can lead to conjunctivitis.

To treat such reaction, affected area should be washed as soon as possible. You should not scratch or itch it to prevent its spread to other areas. You should visit your dermatologist for moderate and severe cases.

Systemic allergic reactions

Few patients may have severe anaphylaxis reactions to some insect bite or stings. Such patients need emergency care.

Specific insect bites

Mosquitoes bites

These are most common insect bites.

• It can cause local reaction in form of local pain, itching, redness and mild swelling or red bumps. Usually they subside in 24-48 hours. Sometimes large firm lesions may develop that may need medical treatment.
• Papularurticaria is another common reaction after mosquitoes bite. (Described above)
• Rarely systemic allergic reaction can occur.
• Disease transmission by mosquitoes bite.

Ticks Bite

Primary concern of tick bite is disease transmission; tick paralysis and allergic reaction are other manifestations. Lyme borreliosis (Lyme disease) is one of most frequently reported tick-borne human disease. Other diseases are Rocky Mountain spotted fever (RMSF), human ehrlichiosis and babesiosis.

Mite bite

Scabies (read more about in scabies section)
Demodex– It usually causes red itchy bumps (solid or pus filled) lesions mainly on face. Sometimes it may mimic rosacea and in severe cases it can cause nodulocystic lesions.

FAQs

What is a normal reaction to an insect sting?

Insect sting can lead to painful warm swelling.

What can be done to reduce symptoms of insect sting?

• Wash the area with soap and cool water
• Keep the area clean and try not to scratch it
• Put a cold, damp washcloth on the area
• Take or apply anti-itch medicine
• Take a nonprescription pain medicine for the pain

How to prevent insect bite or sting?

• Wear full-sleeved shirts, long pants, shoes when you go outside.
• Insect repellant
• When mosquitoes are active, stay inside. Use mosquitoes nets during sleep.
• Drain areas of standing water.
• Keep food and drinks covered.
• If you notice any stinging insect, stay calm and move back.
• Pest control

For more information on Insect bite reaction or to inquire about other services please contact us on 7726938335.