Overview
Venom allergy is an IgE-mediated hypersensitivity reaction that occurs after a sting from venomous insects such as bees, wasps, hornets, and ants. In sensitized individuals, the immune system mistakenly identifies venom proteins as harmful and produces allergen-specific IgE antibodies. On re-exposure, these antibodies trigger mast cell degranulation and release of histamine and other inflammatory mediators. This leads to a spectrum of reactions ranging from mild local swelling to severe, life-threatening anaphylaxis. Venom allergy is considered a medical emergency condition due to the risk of rapid systemic reactions and requires early recognition, accurate diagnosis, and preventive management strategies
Symptoms
Symptoms of venom allergy vary in severity and onset. Local reactions include redness, itching, pain, and swelling at the sting site, which may become extensive in large local reactions. Systemic symptoms indicate a more serious allergic response and include widespread hives, flushing, and angioedema involving the lips, tongue, or throat. Respiratory symptoms such as throat tightness, wheezing, shortness of breath, and difficulty breathing are common in severe cases. Gastrointestinal symptoms may include nausea, vomiting, abdominal cramps, and diarrhea. Cardiovascular symptoms such as dizziness, fainting, and a rapid drop in blood pressure signify anaphylaxis. These symptoms often develop rapidly and can progress within minutes after a sting.
Causes
Venom allergy is caused by exposure to allergenic proteins, enzymes, and peptides present in insect venom. Common venom sources include honeybees, paper wasps, yellow jackets, hornets, fire ants, bumblebees, and other stinging ants. During the sensitization phase, initial exposure leads to the production of venom-specific IgE antibodies. Subsequent stings cause cross-linking of IgE on mast cells, resulting in mediator release and systemic allergic reactions. Multiple stings can increase venom load and worsen reactions. Certain insects are more likely to cause severe reactions due to venom composition and delivery mechanism.
Risk Factors
Risk factors for venom allergy include a previous history of systemic allergic reaction to an insect sting, which is the strongest predictor of future severe reactions. Adults, particularly between thirty and fifty years of age, are at higher risk than children. Underlying heart disease increases the severity and risk of complications. Mast cell disorders significantly elevate the risk of severe anaphylaxis. Use of medications such as beta-blockers may worsen outcomes by interfering with treatment response. Stings near the head or neck and exposure to multiple stings at once further increase the risk of life-threatening reactions.
Prevention
Prevention of venom allergy focuses on avoidance, preparedness, and long-term management. Avoiding insect nests and areas with high insect activity reduces exposure risk. Wearing protective clothing such as long sleeves, trousers, and closed footwear during outdoor activities is recommended. Avoiding bright colors, floral patterns, and uncovered food or drinks outdoors helps prevent attracting insects. Individuals with known venom allergy should carry epinephrine auto-injectors at all times and be trained in their use. Venom immunotherapy is an effective preventive treatment that significantly reduces the risk of future systemic reactions. Patient education, early diagnosis, and adherence to preventive strategies are essential to reduce morbidity and mortality associated with venom allergy.
