Anaphylactic reactions (anaphylaxis) after insect bites

Depending on how severe they are, anaphylactic reactions usually affect the skin, the digestive tract, the airways and the cardiovascular (heart and blood vessel) system. The severity of the reaction can be described using four grades.

Anaphylactic reactions can vary greatly from person to person, or from one reaction to the next. The symptoms may get worse within only a few minutes. They then often stay at the same level of severity for a while and then go away again on their own. The different symptoms may occur alone, after one another, or at the same time. They might return again within 24 hours, even if they have already been treated.

Early signs of anaphylaxis may include the following:

• A metallic taste in your mouth
• A burning sensation on the palms of the hands and soles of the feet
• Burning, tingling or itching on the tongue or roof of the mouth
• Feeling afraid
• Headache
• Confusion

The most common triggers of severe anaphylactic reactions in children are foods (usually peanuts, walnuts and hazelnuts, fish, chicken eggs or cow's milk), followed by insect venom and medication. In adults, the most common trigger is insect venom, followed by medication and foods.

Certain factors can increase the likelihood of anaphylaxis. These include physical exertion, alcohol and infections. Severe anaphylaxis is more common in older people, as well as in people with severe cardiovascular disease or poorly controlled asthma.

Anaphylactic reactions are also a possible side effect of allergen-specific immunotherapy (desensitization).

First and foremost, it is important to stay calm and

• as soon as you notice mild symptoms of anaphylaxis, call the emergency services (112 in Germany and many other countries, 911 in the U.S.) and tell them that you think it's an anaphylactic reaction.
• inform people around you so that they can help if necessary.
• if you have an emergency kit with medication, use it as specified.
• depending on the symptoms (see below), lie down flat on your back or sit down.

If the symptoms are severe (e.g. breathing difficulties or loss of consciousness), the adrenaline (epinephrine) should be injected before calling the emergency services, if possible.

Keeping a sample of the potential trigger may make the diagnosis easier.

Strenuous physical activities should be avoided. Whether it's best to lie down or sit down will depend on the symptoms. A lying position is more suitable in most cases. If the person is finding it hard to breathe, a (half-)sitting position is better. If they are unconscious, or drifting in and out of consciousness, the recovery position is safest. In the event of circulatory shock, elevating the legs improves blood circulation. It might be hard to put children into a particular position because they are often scared, and move around a lot. It is then better to pick them up and hold them.

If the blood stops circulating around the body, a pulse will no longer be felt. It is then important to start doing CPR (cardiopulmonary resuscitation) immediately. In other words:

• Place your hands on the breastbone and – keeping your arms outstretched – press down repeatedly at a rate of 100 to 120 times per minute (about two times every second).
• Trained first-aiders should also breathe into the person's mouth using a compression-to-breath ratio of 30 to 2. That means that after doing 30 heart compressions, they should breathe into the unconscious person's mouth or nose twice, then do another 30 compressions, followed by another two breaths, and so on.
• The heart compressions shouldn't be stopped for longer than ten seconds.

CPR should be continued until the heart starts pumping again or the emergency services arrive.

The main medication used in the treatment of anaphylactic reactions is adrenaline (also called epinephrine). It improves blood circulation, makes it easier to breathe and reduces swelling of the skin. Adrenaline starts working within a few minutes. It is usually injected into a thigh muscle. If it isn't effective enough, another injection can be given five to ten minutes after the first injection.

According to current recommendations, it is also a good idea to take an antihistamine and – depending on the situation – a steroid medication as soon as possible. Both of these medications take longer to start working than adrenaline, but also aim to further reduce the allergic reaction.

If it is thought that the person's heart might stop beating, adrenaline is injected into a vein, or put into a vein using an infusion (a "drip"). If their throat swells up and their airways tighten, they are also given adrenaline through a breathing mask, together with oxygen.

If their breathing and heartbeat become very weak, they are given oxygen through a breathing mask. Sometimes a tube has to be inserted into the person's windpipe to allow them to breathe, but that is only rarely necessary. In the event of circulatory shock, the person is quickly given a lot of fluids through an infusion (drip) in order to stabilize their circulation.

Emergency kits can be used to quickly treat anaphylaxis. They can either be used by the person themselves or by other people who are with them. Emergency kits contain the following:

• An adrenaline (epinephrine) injection with a device that helps you inject it, known as an auto-injector
• An antihistamine in the form of a liquid or tablet
• A steroid medication in the form of a suppository, liquid or tablet
• In people who have asthma: an inhaler to open up their airways
• In people who tend to have breathing difficulties: an adrenaline inhaler to breathe in
• Instructions explaining how to deal with anaphylaxis
• People who have had an anaphylactic reaction in the past are advised to carry a medical ID card or bracelet on them at all times, to let people know what they are allergic to and which doses of the medications should be used

Doctors can prescribe emergency kits for people who

• have had an anaphylactic reaction in the past, unless the trigger can be avoided (like most medications can).
• are known to have mastocytosis. In this rare disorder, certain immune cells in the tissue start multiplying a lot. Mastocytosis can occur in various organs, causing symptoms such as stomach ache, itching, exhaustion and muscle pain.
• have had an allergic reaction to peanuts, walnuts or sesame oil in the past. These foods are particularly likely to lead to anaphylaxis.
• have an allergic reaction to even small amounts of an allergen (a trigger).

In Germany, the costs of emergency kits are generally covered by statutory health insurers if one or more of these criteria are met.

Patients can participate in patient education programs in which they learn how to deal with anaphylaxis and how to use their emergency kit. It is also important to let other people (e.g. friends, family or coworkers) know how to use the emergency kit, in case they ever have to help.