Wasp Stings Clinical Presentation

Symptoms can vary depending on the reaction of the patient to the wasp sting.

• A localized reaction causes symptoms of redness, swelling, and pain over the site of the wasp sting. The pain begins immediately and gradually worsens as the redness and edema gradually worsen. The localized reaction may last 6-12 hours.
• A patient with a mild allergic reaction may experience itching and hives.
• Severe allergic reactions and anaphylaxis may present in patients as symptoms of a throat-closing sensation, dyspnea, chest tightness, lightheadedness, increased anxiety, headache, nausea, abdominal cramps, and palpitations.

Physical signs vary in severity, depending on host sensitivity to the protein allergens in the venom. This can vary from a local reaction at the site of the wasp sting to a more generalized pruritic urticarial reaction to angioedema, laryngeal spasm, bronchial spasm, and vasomotor collapse of anaphylactic shock.

Local reaction

A raised, painful, erythematous inflammatory reaction may be observed at the site of each wasp sting, usually developing several minutes after the sting.

A minute punctate lesion is visible at the center of the lesion where the wasp sting occurred.

Generalized urticarial reaction

A generalized, allergic, immunoglobulin E (IgE)–mediated reaction that involves only the skin can occur within minutes to hours of the wasp sting.

Patients present with multiple pruritic hives.

Angioedema

Patients may present with signs of airway obstruction with stridor and dyspnea. The voice may be muffled or hoarse. Patients may not be able to process their own secretions and may be drooling or appear to have odynophagia.

Inspection of the oral pharynx may show soft tissue swelling of the mucosa or of the tongue. Normal results on examination of the oral pharynx do not preclude edema and impending obstruction of the larynx.

Anaphylaxis

Impending vasomotor collapse may be associated with the appearance of restlessness or anxiety in patients.

Vital signs include tachycardia, tachypnea, and thready pulses. In the early phase, the BP may be maintained because of increased cardiac output until the patient decompensates.

Skin appearance may vary from a warm flushed appearance shortly after the wasp sting (due to increased vasodilation caused by circulating vasoactive amides) to a cold, pale, diaphoretic appearance late in the event.

Auscultation of the chest may reveal variable results, from wheezing due to bronchospasm and prolongation of the expiratory phase to poor air movement or coarse crackles due to pulmonary edema.

Anaphylaxis is highly likely when any one of the following 3 criteria is fulfilled:

• The acute onset of illness (minutes to several hours), with involvement of the skin, mucosal tissue, or both (eg, generalized hives; pruritus or flushing; swollen lips, tongue, or uvula) and at least one of the following: Respiratory compromise (eg, dyspnea, wheeze or bronchospasm, stridor, reduced peak expiratory flow [PEF], hypoxemia) or reduced BP or associated symptoms of end-organ dysfunction (eg, hypotonia [collapse], syncope, incontinence)

Two or more of the following that occur rapidly after exposure to a likely allergen for that patient (minutes to several hours):

• Involvement of the skin or mucosal tissue (eg, generalized hives; itch or flush; swollen lips, tongue, or uvula)
• Respiratory compromise (eg, dyspnea, wheeze or bronchospasm, stridor, reduced PEF, hypoxemia)
• Reduced BP or associated symptoms (eg, hypotonia [collapse], syncope, incontinence)
• Persistent GI symptoms (eg, crampy abdominal pain, vomiting)

Reduced BP after exposure to a known allergen for that patient (minutes to several hours), as follows:

• Infants and children - Low systolic BP (age specific) or greater than 30% decrease in systolic BP (Low systolic BP in children is defined as less than 70 mm Hg in those aged 1 mo to 1 y, less than 70 mm Hg + [2 X age] in those aged 1-10 y, and less than 90 mm Hg in those aged 11-17 y.)
• Adults - Systolic BP of less than 90 mm Hg or greater than 30% decrease from that person's baseline

Potential risk factors include outdoor activities (recreational or occupational) during the mild-to-warm months of the year. The disturbance of an established wasp nest, which can occur during routine yard work, raking, or trimming bushes that may contain a concealed nest, can result in multiple wasp stings.

• The wearing of any scented material (eg, perfume, hairspray, soaps, deodorants, sunscreen) or brightly colored clothing, especially floral designs, may attract wasps and insects.
• Odors near the home environment (eg, open garbage pails, rotting fruit from fruit trees) may also attract wasps.
• Partially closed or protected areas (eg, in a wood shed, under a car hood) may harbor a wasp nest, and an attack may result if the nest is disturbed.
• In addition, a noted increase of Hymenoptera stings have occurred following environmental disturbances of their customary habitat such as after hurricanes or floods.^[2]