We have all encountered unpleasant itching caused by insect bites. Most of them are completely harmless, accompanied by redness, swelling, pain that passes in a couple of hours or days. Special precautions are necessary in case of people with allergic reactions to toxins, which are introduced into the skin by insects. Children generally react more violently to insect bites, because they are more sensitive to their toxins. Insect bites are more frequent in summer, near rivers and standing waters, when spending time in nature, when we are in brightly coloured clothes, with intense odours on us.
The most important thing when it comes to insect bites is to notice the development of systemic reactions. The appearance of hives, red marks all over the skin, swelling of the soft tissues of the face, nausea, vomiting, difficulty breathing and swallowing, pressure drop and anaphylactic shock are signs that you need to seek urgent medical attention.
Anaphylaxis is rare in mosquito bites, but more common in bee and hornet stings. . 3% of adults in our population and 1% of children are allergic to insect bites. People who have risk of developing anaphylaxis must always carry on them EpiPen – an adrenaline auto-injector used to treat severe allergic reactions in an emergency. Such persons should perform allergen immunotherapy, also known as desensitization with injections of small doses of poison for 2 years, after which they will not have allergies for the next 20 years.
Mosquito bites are very common in summer, in the evening, near water. The female mosquito injects its saliva during bite that contains proteins which cause an immunologic response in the skin. It is characterized by redness, swelling and itching lasting for a couple of hours. Larger swellings occur on the eyelids, lips and areas of skin and mucous membrane contact. Allergic reactions to mosquito bites are more common in children. The swollen areas can be 5 cm in size, red patches have a central blister that turns into a scab, and in surrounding areas hives may appear in the form of red patches. Bacterial infection occurs more often in children at the bite site because they scratch it.
In that case it is necessary to apply antibiotic ointment. To relieve intense itching, it is best to use ice or boric acid compresses and apply corticosteroid ointment. Before going out, spray children with protective products on the basis of plant extracts. Wear light-coloured clothing, long sleeves and trousers, avoid walking along rivers in the evening when mosquitoes are the most active.
Wasp, bee and hornet stings
Wasp, bee and hornet stings in our region most often cause allergic reactions and anaphylactic shock. Wasp stings are very painful, with the immediate onset of redness and swelling that is toxic in nature. The wasp does not leave a stinger, so it can sting several times. Stings in the face, lips, tongue, eyelid area cause large swellings and represent a risk of airway obstruction, so they require emergency medical help.
A bee stings only when it feels threatened, because it loses the stinger and dies. The bee’s stinger is full of poison, it should not be removed from the skin with tweezers or nails, but peeled off the skin with a blunt object. Put ice on the sting site until pain is reduced and apply corticosteroid ointment. If a more intense reaction occurs after a bee sting, with swelling larger than 10 cm or hives, it is necessary to perform tests to determine IgE antibodies to bee venom. If a risk of allergy exits, a person must carry anti-shock therapy on them, because with each subsequent bee sting, the allergic reaction is more intense and can cause anaphylactic shock.
The hornet has a big stinger, its stings are more painful, and the swellings are huge. Hornet has poisons with a higher amount of acetylcholine, which causes general toxic effects in the body, with vomiting, diarrhoea, restlessness. Hornet stings often cause anaphylaxis.
Only a few species of spiders in our region have long fangs, through which the venom is released causing a toxic reaction on the skin. Hard swelling with redness develops, more than 10 cm in diameter, which goes away in 7 days. It is advisable to put ice on the bite site and avoid scratching, because it can get infected and in that case the antibiotic therapy is required. There are people who are allergic tospider bites, developing hives and suffocation and they require urgent hospitalization.
In endemic areas (along the Croatian coast), the most poisonous species of spiders live – the black widow that produces alpha latrotoxin, a neurotoxic and deadly venom. Its bite causes severe pain, stomach cramps, high blood pressure, headache, vomiting, requiring urgent medical attention in order to receive antidotes.
Simulium are small black flies of the genus Simulidae, which appear in early summer, near water. Their bites can be most often found on the lower legs and forearms and are very painful in the form of a bloody spot. After that redness appears, along with a blue swelling of 10 cm in size and an infection develops that spreads to the subcutaneous tissue. The fly’s saliva contains anticoagulant toxins, which are transmitted deep into the skin by scratching, creating large swelling and infection. General symptoms with headache and fever are rare. It is necessary to contact a dermatologist who will prescribe antibiotic and antihistamine therapy.
Dr Slađana Cvejić