Insect allergy

The main forms of insect allergy are:

• local skin reactions to insect bites;
• systemic anaphylactic reactions to stings;
• respiratory allergic reactions to inhalation of insects and substances secreted by them.

A distinction is made between immediate reactions, which occur within a few seconds or minutes and last for several hours or days, and delayed allergic reactions, which appear 1-2 days after the bite.

Toxic reactions are observed after stings from large numbers of insects.

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Causes of insect allergies

Stinging insects belong to the Hymenoptera. Most often, severe systemic reactions occur to bee and wasp bites. Mosquito bites rarely cause severe allergic reactions, since they inject not poison, but a secretion of the salivary glands, which can cause a local allergic reaction. With an abundance of mosquitoes, midges, beetles, butterflies in the summer, it is possible to inhale small insects or wing scales, which can cause respiratory allergies.

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Pathogenesis

An unusual reaction to an insect bite can be mediated by IgE or IgG2 reagins. The main allergenic components of the venom are phospholipase A2, hyaluronidase, melittin, high-molecular fraction with acid phosphatase activity, and allergen C. In addition, venoms and insect saliva may contain histamine, acetylcholine, kinins, other biogenic amines and their liberators, and enzymes. In this case, the reaction is pseudo-allergic.

Symptoms of insect allergy

A pronounced local reaction is manifested by severe swelling and erythema (over 10 cm in diameter), persisting for more than 24 hours. Other signs of an immediate allergic reaction may appear at the same time - urticaria, angioedema, facial flushing; nausea, vomiting; difficulty breathing caused by swelling of the nasopharynx, vocal cords, larynx, trachea, bronchospasm; abdominal pain, diarrhea; arthralgia.

Anaphylactic shock is the most severe allergic reaction to insect bites. Anaphylactic shock can develop with a bite to any part of the body, but its probability increases with a bite to the head and neck area. In most cases, symptoms of anaphylactic shock appear within the first 15 minutes, although a later onset of the reaction is possible. The clinical picture of anaphylactic shock corresponds to that described below.

The more severe the initial reaction to the bite, the higher the likelihood of it recurring.

Serum sickness-like reactions may occur within 7-12 days after the bite.

Insect Allergy Diagnosis

Diagnosis is usually based on history. Skin testing is performed with bee and wasp venom extract. Specific IgE may be measured in vitro.

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Insect Allergy Treatment

Non-specific symptomatic therapy is carried out. The remains of the sting stylet are removed from the skin, cold compresses, antipruritic and anti-inflammatory ointments are applied locally, antihistamines and non-steroidal anti-inflammatory drugs are administered orally.

Specific hyposensitization is carried out with strict determination of indications by one allergen or a mixture of several poisons. Duration of treatment is 3-5 years.

Insect Allergy Prevention

Prevention of reactions to insect bites in susceptible individuals includes the following basic rules:

• in the summer months, go outside in clothes that cover the body as much as possible, choose light, muted colors of clothing;
• do not make any sudden movements when insects appear;
• do not walk barefoot (especially on grass);
• wear a head covering;
• be careful when eating outdoors;
• avoid using preparations containing propolis.

Parents should be trained in first aid for insect bite reactions.