Wasp Stings
Wasps belong to the order Hymenoptera, suborder Apocrita. This order, which encompasses bees, yellow jackets, hornets, and ants, is distributed globally. Hymenoptera stings result in a higher number of fatalities in the United States than any other type of envenomation. The order Hymenoptera comprises Apis species, which include bees (European, African), vespids (wasps, yellow jackets, hornets), and ants (refer to the images below). Most fatalities arise from immediate hypersensitivity reactions and anaphylaxis.
Wasps can be classified into social wasps and solitary wasps. Social wasps encompass the aggressive species found in northern temperate regions, such as the yellow jacket (characterized by black and yellow bands on the abdomen) and the hornet (predominantly black with yellow markings on the face and thorax). Social wasps exist in colonies that can consist of a dozen to several hundred mature individuals. The colonies may vary in size and location, from the underground nest of the yellow jacket, located in decayed tree stumps and animal burrows, to the hornet's paper nest suspended from shrubs, trees, or affixed to the side of a shed or residence.
Upon breaching the skin, the muscles surrounding the wasp's venom sac initiate the injection of the venom. Wasp venom comprises up to 13 distinct antigens. The wasp sting initially induces a severe stinging sensation. In the general populace, 3% of adults and less than 1% of children experience systemic reactions. This is likely due to adults having a greater likelihood of developing sensitization from a previous wasp sting.
Potential risk factors include outdoor activities (recreational or occupational) during the mild-to-warm months of the year. Disturbing an established wasp nest, which can happen during standard garden maintenance, such as raking or trimming bushes that may conceal a nest, can result in multiple wasp stings. The prognosis for mild-to-moderate reactions is favorable. The objective is to prevent further exposure.
Wearing scented materials (e. g. , perfume, hairspray, soaps, deodorants, sunscreen) or brightly colored clothing, particularly those with floral patterns, may entice wasps and other insects. Odors in the vicinity of the home (e. g. , open garbage bins, decaying fruit from trees) may also draw wasps. Partially enclosed or sheltered areas (e. g. , in a wood shed, under a car hood) may conceal a wasp nest, and an attack may ensue if the nest is disturbed. Furthermore, a notable increase in Hymenoptera stings has been observed following environmental disturbances to their typical habitat, such as after hurricanes or floods.
Risk factors for severe anaphylaxis include the following:
Advanced age, potentially linked to elevated tryptase levels associated with the aging process.
Concurrent pulmonary diseases (e. g. , asthma, chronic obstructive pulmonary disease).
Existing cardiac conditions (e. g. , congestive heart failure, cardiomyopathy, valvular disease).
Mastocytosis or clonal mast cell disorders.
Severe allergic conditions such as allergic rhinitis.
Medications including beta-blockers and ACE inhibitors.
The anaphylactic reaction commences with the manifestation of symptoms distal to the wasp sting. The patient often experiences heightened anxiety, dizziness, headache, nausea, abdominal cramping, and palpitations. This is succeeded by observations of the patient appearing flushed, hypotensive, and exhibiting tachycardia (elevated heart rate).
Treatment
Local wound management:
Apply ice to maintain a comfortably cool temperature in the affected area and to diminish swelling. Unlike honeybee stings, members of the wasp family (including hornets and yellow jackets) typically do not lose their stinging apparatus in the wound. Consider the possibility of a secondary bacterial infection at the site in patients who present several days post-sting with fever or ongoing redness, warmth, swelling, and tenderness around the site or progression of the redness.
Anaphylaxis emergency intervention:
The patient may present with airway obstruction, respiratory impairment due to bronchospasm, or circulatory collapse, or a combination of these three conditions. Adhere to the ABCs of emergency medicine as swiftly as possible. The airway must be secured. Intubate the patient using rapid sequence intubation upon evidence of imminent airway obstruction due to swelling or signs of respiratory failure stemming from bronchospasm. It is more manageable to extubate a patient than to delay and attempt to pass a tube through an edematous (swollen) larynx. Establish two large-bore intravenous lines to facilitate medication administration and fluid bolus in the occurrence of circulatory collapse. Position the patient on both pulse oximetry and a cardiac monitor. Administer adrenaline (Epinephrine), 0. 3-0. 5 mL of a 1:1000 solution, intramuscularly.
Delayed reactions may occur in 4% of severe allergic reactions and can manifest up to 72 hours following exposure. Risk factors include a prior history of anaphylaxis, an unknown trigger, and a delay in the use of adrenaline/epinephrine exceeding 60 minutes from the onset of symptoms.
Counsel patients who have experienced an allergic reaction to previous wasp stings or any Hymenoptera stings to exercise caution while outdoors during mild-to-warm weather. Advise these patients to refrain from wearing any scented products (e. g. , perfume, hairspray, soaps, deodorants, sunscreen). Brightly colored apparel, particularly floral patterns, should be avoided. Recommend that the patient be accompanied when outdoors and away from populated areas (e. g. , hiking, fishing) in case assistance is required.
Encourage patients to carry EpiPen auto-injectors while outdoors and to have one device available at home. Inform the patient that auto-injectors left in a vehicle for extended periods on hot days may lose efficacy. They should regularly check the expiration date of the auto-injectors.
