Hymenoptera stings
Background
- All Hymenoptera share similar components in their venonm and patients can have allergies across the subgroups[1]
- Most reactions are local but anaphylaxis and serum sickness are possible
Bees (Apids)
- Include Bumblebees and Honeybees
- Barbed Stingers - remain in victims and the process of stinging kills the bee
- Killer bees (hybridized African Bees) have small individual toxin potency but attack in large numbers with increased aggression[2]
- Main allergen is phospholipase A2, hyaluronidase and melittin[1]
- redness and irritation last 1-3 days
Wasps (Vespids)
- Include Yellow Jackets, Hornets, and Wasps
- Non barbed stinger - can sting multiple times and the sting does not cause the wasps' death
- Histamine, phospholipase, antigen 5, and bradykinin similar to bees[1]
- Redness and irritation last 1-3 days
Fire Ants (Formicidae)
- Solenopsis invicta (red fire ant) and Solenopsis richteri (black fire ant)
- Alkaloid venom
- Intense burning papules that may turn to pustules in 24hrs
- Localized necrosis has also been reported[3]
Clinical Features
Local Reaction
- Urticarial lesion contiguous with sting site
- Severe local reaction may involve one or more neighboring joints
- Local reaction occurring in mouth or throat can produce airway obstruction
- Local reaction occurring around eye can result in cataract, iris atrophy, globe perforation
Toxic Reaction
- Occurs after multiple stings
- May be delayed 8-24hrs
- Venom mediated, not IgE
- Resembles anaphylaxis but greater frequency of nausea/vomiting and diarrhea
- Other symptoms: light-headedness, syncope, headache, fever, drowsiness, muscle spasms
- Massive stings can result in renal or hepatic failure, DIC, rhabdo
- Systemic toxicity more likely if > 50 stings
- Median lethal dose of honeybee venom ~19 stings/kg or 500-1400 stings per human
Anaphylactic reaction
- Majority occur within first 15min; nearly all within 6hr
- No correlation with number of stings
- IgE mediated, rather than direct response to the venom.
- Shorter the interval between sting and onset of symptoms the more severe the reaction
Delayed Reaction
- May occur 5-14d after a sting
- Serum sickness features (fever, malaise, urticaria, lymphadenopathy, polyarthritis)
Differential Diagnosis
Envenomations, bites and stings
- Hymenoptera stings (bees, wasps, ants)
- Mammalian bites
- Closed fist infection (Fight bite)
- Dog bite
- Marine toxins and envenomations
- Toxins (ciguatera, neurotoxic shellfish poisoning, paralytic shellfish poisoning, scombroid, tetrodotoxin
- Stingers (stingray injury)
- Venomous fish (catfish, zebrafish, scorpion fish, stonefish, cone shells, lionfish, sea urchins)
- Nematocysts (coral reef, fire coral, box jellyfish, sea wasp, portuguese man-of-war, sea anemones)
- Phylum porifera (sponges)
- Bites (alligator/crocodile, octopus, shark)
- Scorpion envenomation
- Reptile envenomation
- Spider bites
Evaluation
- Usually clinical
Management
- Stinger Removal
- Immediate removal is the most important principle; the method of removal is irrelevant
- Local wound care and tetanus prophylaxis
- Oral Antihistamines provide symptom relief for pruritus
Local Reaction
- Ice packs diminish swelling and delays absorption of venom
- NSAIDs and antihistamines for comfort
- Infection is uncommon, but may present as ongoing swelling or cellulitis
Systemic reaction
- Treat similar to anaphylaxis
Disposition
- Normally outpatient, unless anaphylaxis or systemic toxicity
- EpiPen should be prescribed on discharge if significant reaction
- Admission/observation for victims with >100 stings, substantial comorbidities, those at extremes of age
See Also
References
- ↑ 1.0 1.1 1.2 King TP et al. Structure and biology of stinging insect venom allergens. Int Arch Allergy Immunol. 2000;123(2):99-106
- ↑ Díaz-Sánchez C. et al. Suvival after massive (>2000) Africanized Honey bee stings. Arch Intern Med. 1998;158(8):925-927
- ↑ Fernández-Meléndez S. et al. Anaphylaxis caused by imported red fire ant stings in Málaga, Spain. J Investig Allergol Immunol. 2007;17(1):48-49
Review Questions