Allergies: allergic reactions to insect stings

Bee, wasp, hornet or ant stings are the insect stings that most often trigger allergic reactions. However, most people are not allergic to insect stings and may mistake a normal sting reaction for an allergic reaction. By knowing the difference, you can prevent unnecessary worry and visits to your GP. 

The severity of an insect sting reaction varies from person to person. There are three types of reactions - normal, localised and allergic: 

• A normal reaction will result in pain, swelling and redness around the sting site. 
• A large local reaction will result in swelling that extends beyond the sting site. For example someone stung on the ankle may experience swelling of the entire leg. While it often looks alarming, it is generally no more serious than a normal reaction. 
• The most serious reaction to an insect sting is an allergic one (described below). This condition requires immediate medical attention.

What are the symptoms?

Symptoms of a severe allergic reaction (called an anaphylactic reaction) may include one or more of the following:

• Difficulty breathing
• Hives that appear as a red, itchy rash and spread to areas beyond the sting
• Swelling of the face, throat or mouth tissue
• Wheezing or difficulty swallowing
• Restlessness and anxiety
• Rapid pulse
• Dizziness or a sharp drop in blood pressure

Although severe allergic reactions are not that common, they can lead to shock, cardiac arrest and unconsciousness in 10 minutes or less. This type of reaction can occur within minutes of a sting and can be fatal. Get emergency treatment as soon as possible.

A mild allergic reaction to an insect sting may cause one or more of the following symptoms at the site of the sting:

• Pain
• Redness
• Pimple-like spots
• Mild to moderate swelling
• Warmth at the sting site
• Itching

People who have experienced an allergic reaction to an insect sting have a 60% chance of a similar or worse reaction if they are stung again.

How common are sting allergies?

Only a small percentage of individuals in the UK develop severe reactions (anaphylaxis) from the venom of stinging insects.. According to the NHS, there are 2-9 deaths every year in the UK due to anaphylaxis from bee or wasp stings.

How are normal or localised reactions treated?

• First, if stung on the hand, remove any rings from your fingers immediately.
• If stung by a bee, the bee usually leaves a sac of venom and a stinger in your skin. Remove the stinger within 30 seconds to avoid receiving more venom. Gently scrape the sac and stinger out with a fingernail or a stiff-edged object such as a credit card. Do not squeeze the sac or pull on the stinger - this will cause the release of more venom into the skin.
• Wash the stung area with soap and water; then apply an antiseptic.
• Apply a soothing ointment such as a hydrocortisone cream or calamine lotion and cover the area with a dry sterile bandage.
• If swelling is a problem, apply an ice pack or a cold compress to the area.
• Take an over-the-counter oral antihistamine to reduce itching, swelling and hives. However, this medication should not be given to children under 2 years old or to pregnant women without prior approval from a doctor.
• To relieve pain take a non steroidal anti-inflammatory medication such as ibuprofen.
• In general pregnant women should consult their doctors before taking any over-the-counter medicine.
• Also, carefully read the warning label on any medicines before taking it. Parents of children and people with medical conditions should consult a pharmacist if they have questions about a medicine's use.