Insect bite allergy is the development of a hypersensitivity reaction to the components of venom, saliva and other substances that enter the human body through contact with arthropods. In this case, an allergic reaction can be immediate or delayed, clinical manifestations are local – in the form of swelling, redness or general – up to anaphylactic shock. Allergy diagnosis includes the collection of anamnesis, analysis of the symptoms of the disease and laboratory data. Treatment – removal of the allergen and reduction of its absorption, anti-shock measures, ASIT.
W57 Bite or sting by non-venomous insects and other non-venomous arthropods
Insect bite allergy and stings, as well as hyperreaction in contact with their waste products (insect allergy) is found in every tenth inhabitant of our planet. The most dangerous allergic reaction to the venom of hymenoptera stinging insects, which often ends in anaphylactic shock and death. Sensitization to the venom of bees, wasps, hornets develops more often in young patients under the age of 20, including children and adolescents.
Most often, acute allergic reactions occur when bites of hymenoptera stinging insects: bees, bumblebees, wasps, hornets, and ants. The venom that penetrates the body during a bite contains a large number of high-molecular proteins-enzymes, basic peptides, biogenic amines, which lead to the development of a cascade of undesirable reactions. These are local changes in the bite area (vasodilation and increased permeability, irritation of pain receptors), the toxic effect of the absorbed poison and the allergic reaction itself.
When bitten by blood-sucking insects: mosquitoes, midges, horseflies, bedbugs, fleas, various biologically active elements with toxic, anticoagulant effect penetrate into the skin with saliva and often cause the development of hypersensitivity. Allergies can occur to the bites of beetles, cockroaches, some varieties of butterflies, as well as in contact with insect waste products.
Sensitization with insect allergy develops in several ways: parenteral (when stung, bitten), aerogenic (ingestion of insect particles and their excrement into the respiratory tract with household dust), contact, alimentary (when eating). The main mechanisms of the pathological process are caused by the occurrence of allergic reactions of the immediate type, immunocomplex and pseudoallergic reactions.
With the immediate response of the immune system, specific IgE immunoglobulins are produced for a specific type of insect allergen. In this case, the symptoms of the disease usually appear in the first 10-20 minutes after the bite. The immunocomplex type of reactions is accompanied by the synthesis of IgG and the formation of circulating immune complexes, with pseudoallergia, the pathological process is triggered by biologically active components contained in insect venom and saliva.
Symptoms of insect bite allergy
Clinical signs of allergy can be local (limited to the place of sting or bite), organ (characterized by a violation of the function of target organs) and generalized, when the pathological process is systemic, disrupts the work of the whole organism and poses a serious threat to life. Local changes are characterized by the appearance on the skin of a local focus of redness and swelling ranging in size from 7-10 centimeters in diameter, accompanied by severe itching of the skin. Sometimes papular rash, localized areas of necrosis, blisters may occur in the bite area. With combing and rejection of the epidermis, infection is possible.
Systemic manifestations of allergy to arthropod bites can be mild (common rash, itching, anxiety), pronounced (attachment of dizziness, pain behind the sternum and along the bowel, dyspepsia), severe (hoarseness of voice, shortness of breath, suffocation, fear of death, constipation). In extremely severe cases, an anaphylactic reaction develops after a bite with a marked decrease in blood pressure, loss of control over the function of the pelvic organs, the appearance of constipation and coma, respiratory arrest and cardiac activity, which, in the absence of emergency care, ends in death.
Organ manifestations of allergy are quite rare and are characterized by the development of vascular inflammation by the type of vasculitis, lesions of the heart muscle, kidney tissue, brain, joints, peripheral nervous system and the appearance of symptoms occurring in these diseases. Direct contact with insect bodies and their excrement sometimes leads to the appearance of symptoms of rhinoconjunctivitis, stomatitis, bronchospasm, dyspepsia.
The main task of a specialist in the field of modern allergology at the stage of diagnosis is a thorough collection of anamnestic data (the presence of allergic reactions in the past during contact with insects, establishing the fact of a bite, the type of arthropod, etc.), an attentive clinical examination (identification of symptoms of skin lesions, the presence of signs of generalization and organ disorders). If necessary, additional studies are prescribed to help diagnose systemic and organ disorders (general and biochemical blood analysis, urine analysis, ECG, spirography, ultrasound of the abdominal cavity, etc.).
Special tests used in the diagnosis of allergic diseases are performed. Among them are skin allergy tests with insect allergens (tests should be carried out only by an allergist in a specialized office), laboratory tests to identify specific immunoglobulins to allergens and other studies. Differential diagnosis of insect bite allergy is carried out with other allergic reactions (urticaria, Quincke’s edema, rhinitis and conjunctivitis, bronchospastic conditions), contact dermatitis, various toxic reactions, diseases of internal organs. You may need to consult a dermatologist, cardiologist, nephrologist, rheumatologist and other specialists.
Treatment of insect bite allergy
In case of local reactions, outpatient treatment. With the development of anaphylactic shock, systemic and organ reactions, treatment and follow-up in a hospital are indicated. Therapeutic measures for insect bite allergy provide for the speedy removal of the allergen from the body and a decrease in its absorption, symptomatic treatment and ASIT.
Elimination of the allergen. If there is a sting, it is removed. A tourniquet is applied above the bite site for 20 minutes and cold locally. It is necessary to ensure peace and an elevated position of the limb.
Medications. Antihistamines of the first and second generation, glucocorticosteroid hormones, pressor amines, bronchodilators and other medications indicated to normalize the function of the affected organ or system are used.
ASIT. Allergen-specific immunotherapy is carried out according to indications in a specialized allergological office.
Prognosis and prevention
With timely access to a specialist and the provision of qualified medical care, insect bite allergy in most cases ends favorably with full recovery of working capacity. With the development of severe systemic and organ lesions, the prognosis worsens.
Prevention provides for sanitary and educational work, restriction of stay near apiaries and other places where insects can accumulate (fruit and vegetable markets, garbage dumps, etc.), the use of protective equipment (masks, nets, clothing), maintaining cleanliness in the premises, treatment with chemical agents to scare away and destroy arthropods. If you have a history of insect bite allergy, you should draw up and carry with you a passport of a patient with an allergic disease and a set of medications (anti-shock kit).