The following information about bumblebee stings provides guidance for reducing the chances of being stung and for treating possible allergic reactions to a sting. The poster version of Bumblebee stings and allergies can be downloaded here.
Bumblebees are part of the natural ecosystem in many countries and, just like honeybees, they are also used commercially as pollinators of agricultural and horticultural crops. There exist a variety of bumblebee subspecies with differing appearances, colours and patterns. In general, bumblebees are larger than honeybees and hairier than wasps. A shared trait among bumblebees, honeybees and wasps is that workers and queens have a stinger, but drones cannot sting. The stinger is a weapon for defence, and when a bee stings, some venom is injected into the body through the stinger. In humans, this generates a short severe pain that gradually fades away. Occasionally (in approximately 1% of cases), people can develop an allergic reaction to the injected venom, and the response to a bumblebee sting can differ from one stinging incident to another. Bumblebee and wasp stingers have no barbs, unlike honeybees who have barbed stingers. This means that a bumblebee worker or queen can withdraw her stinger and is able to sting again multiple times. When a honeybee tries to withdraw its stinger, it tears loose from the abdomen, taking the venom gland with it and killing the bee.
Bumblebees rarely sting, but the chances of being stung can be further reduced by not provoking them or making them aggressive. First of all, it is important to be calm when working with bumblebees. Do not wave your arms at the bumblebees, bump the hive, touch or hold the bees, etc.
Also, be aware that bumblebees can react aggressively to smells such as alcohol, perspiration, perfumes, scented soaps, aftershave, etc. Moreover, rings, bracelets and watches may cause aggressive behaviour (due to the scent of oxidized material between the skin and the jewellery). Bumblebees are attracted to the colour blue, particularly light blue, and this holds true for blue-coloured clothing. Wearing protective clothing can reduce the risk of stings, as bumblebees are able sting through regular clothes.
Usually a bumblebee sting leads to a local, non-allergic reaction: swelling, itchiness and redness at the site of the sting, lasting only a couple of hours. This can occur immediately after the sting, but more generally it occurs a few hours later. The swelling or itching may last for several hours or even days. In some cases, the local reaction may spread somewhat. In these cases, it usually takes longer for the symptoms to disappear; however this still counts as a local, non-allergic reaction.
Usually medical treatment is not necessary. Some measures can be taken to minimize the local reaction, in particular if the person was stung in a sensitive location, such as near the eyes. As soon as possible after being stung, the person should take an anti-inflammatory medication (such as aspirin or ibuprofen) and apply a cold compress to the site. A number of anti-itch ointments are also available (e.g. containing diethyl-m-toluamide). Remove any rings, watches or bracelets if stung on the hand.
In the rare case of a sting in the mouth or pharynx, the patient should be taken to hospital immediately, because a sting of this nature can cause the airways to close up and obstruct breathing. At the hospital, the patient will be given corticosteroids (such as prednisone) and will be kept for observation.
In about 1% of the population, repeated stings (or in some cases only two or three stings) may lead to an allergic reaction, also called a general allergic reaction, a systemic allergic reaction, or an anaphylactic reaction. Because an allergic reaction involves antibodies formed during a previous exposure to an antigen, it is not possible to have an allergic reaction to the first sting. Allergic reactions usually become evident very quickly following the sting (within a few seconds to half an hour).
Allergic reactions are classified in four levels, in order of increasing severity:
Level 1 - itching, redness and swelling (urticaria, hives) over the whole body.
Level 2 - level 1 symptoms plus intestinal problems (vomiting, diarrhea).
Level 3 - level 1 and/or 2 symptoms plus difficulty breathing and/or a feeling of suffocation.
Level 4 - level 1 and/or 2 and/or 3 symptoms plus heart palpitations, fainting, anaphylactic shock (accompanied by dizziness, excessive sweating and cold shivers)
In the event of a fever or a level 1 reaction, contact a GP (general practitioner). The decision can be made to keep an eye on the situation to see how the symptoms progress. A period of observation in hospital is desirable, as the severity of the reaction may increase progressively over time.
In the event of vomiting, and definitely in the case of level 3 or 4 symptoms, the victim should be taken to hospital immediately. Transportation by ambulance is recommended.
In all cases, only a physician is in a position to make a decision regarding treatment, based on the patient's condition and medical history.
If an allergic reaction occurs, administration of a prescription-strength antihistamine (such as clemastine) is helpful. The antihistamine reduces the swelling caused by histamine in the venom. Sometimes corticosteroids (such as DAF/Dexamethasone) are prescribed. In the case of level 3 or 4 reactions, it is necessary to administer adrenaline first. Adrenaline stimulates the heart, constricts the blood vessels and opens the airways. Adrenaline can be self-administered by means of an adrenaline auto-injector (such as an EpiPen or Jext). Adrenaline auto-injectors are only available by prescription, when a patient has already had an allergic reaction to a bumblebee sting, for example. Depending on local legislation, an adrenaline auto-injector may also be available to companies that work with bumblebees.
Toxic reactions only occur if a victim is stung dozens of times in a brief period. General allergic reactions can occur in the nervous or circulatory system, including cardiac arrhythmia or difficulty breathing. In this case as well, the victim should be taken to hospital for treatment and observation.
In addition to a severe level 4 allergic reaction, hyperventilation, perhaps as a result of shock, may also cause loss of consciousness. In these cases it is also necessary to call emergency medical services immediately.
People who use certain medicines (beta-blockers) and pregnant women are at increased risk when allergic reactions occur following a bumblebee sting.
If you have experienced an allergic reaction once, you will not necessarily have an allergic reaction to the next sting. If you had a level 1 or 2 reaction in particular, the likelihood of another reaction is small. Reactions to bumblebee stings may differ in each case. Medical testing is available that uses purified bumblebee venom to determine whether you will have an allergic reaction the next time you are stung. It is also possible to use the purified venom for a hyposensitization treatment.
However, immunotherapy with honeybee or wasp venom does not necessarily protect patients with a bumblebee allergy, and vice versa. This treatment is intended to desensitize the body to bumblebee venom. If you do not wish to undergo hyposensitization treatment, you can obtain a prescription for an adrenaline auto-injector (such as an EpiPen or Jext) from your doctor. You can carry this device with you and use it to inject epinephrine into the thigh in the event of a sting.
Detailed information regarding the medical treatment of allergic reactions is available from Koppert on request. For further information, contact an allergist or a doctor of internal medicine.
De Groot, H. Allergie voor insecten, Huisarts en Wetenschap 2002; 45 (7): 362-7.
De Groot, H. Allergy to bumble bees. Curr Opin Allergy Clin Immunol 2006; 6: 294-7.
A printed poster showing the images used above is available from Koppert. This poster is also available as a download.
Tip: Add the contact information for local medical assistance and emergency medical treatment on the poster.
This information is intended as an educational resource only and should not be used for diagnosing or treating any health problem as it is not a substitute for medical care. If you have or suspect you may have a health problem, please consult a doctor.