Bee or Wasp Sting

While jogging in a local park in Hong Kong, a 55-year-old, previously healthy man was stung on the ventral aspect of his right wrist. The tiny stinger was gently removed with nail cutters and examined under a microscope at 80x magnification; plucking the stinger is ill-advised as this may inject more venom into the wounded site. Two days after stinging, the microscopic appearance of the stinger confirmed the diagnosis to be from a bee instead of a wasp or other insect. A simple method of confirming the nature of insect stings and an overview of Hymenoptera stings and their management are provided herein.

While jogging in a local park in Hong Kong on a hot summer evening, a 55-year-old, previously healthy man was stung on the ventral aspect of his right wrist. Differential diagnosis included a bee, wasp, or other insect sting. The authors present a simple method of confirming the diagnosis of insect stings by gently removing the stinger with nail clippers and evaluating it microscopically, and they provide an overview of Hymenoptera stings and their management. 

While jogging in a local park in the metropolitan city of Hong Kong at about 7:30 PM (temperature 30°C; humidity 90%), a 55-year old, previously healthy man was stung on the ventral aspect of his right wrist. An intense, hot, painful feeling was experienced immediately following the sting for about 1 to 2 minutes over the mid-wrist area. The area became slightly swollen and erythematous (Figure 1). The patient gently removed a fine, tiny, black stinger with nail clippers after returning home 1 hour later. He did not sleep well and felt feverish that night. The next morning, about 12 hours after sting, the wounded site remained painful, and he took anti-inflammatory medication (diclofenac sodium) by mouth. Over the next 48 hours, local pain resolved and he was systemically well. The patient did not receive care at a clinic or medical facility. 

Differential diagnosis included a sting from a bee, wasp, or other insect. A simple method of confirming the diagnosis of an insect sting is described by removing the stinger with nail clippers and microscopic evaluation. The tiny stinger was removed gently with nail clippers; however, plucking the stinger from the wound is ill-advised as this may push more venom into the skin. Under a microscope at 80x magnification, the stinger appeared pointed with a bulb (Figure 2). A milder recovery course with prompt subsidence of localized discomfort in this case (resolution of local pain with symptomatic treatment), stinger removal and symptomatic treatment with anti-inflammatory medication, and microscopic evaluation of the stinger 2 days after wounding confirmed the diagnosis to be a bee sting. 

Arthropods are invertebrates with chitinous exoskeletons, bilateral symmetry, true segmentation, and jointed true appendages that include insects, arachnids, centipedes, crustaceans, and millipedes. Insecta include sucking lice (Anoplura); fleas (Siphonaptera); bedbugs (Hemiptera); flies and mosquitoes (Diptera); bees, wasps, and ants (Hymenoptera); beetles (Coleoptera); and moths and butterflies (Lepidoptera). Insect bites and stings are significantly different.^1,2 Nonvenomous insects bite from the mouthpart; their saliva contains anticoagulants and enzymes that can cause local irritation and allergic reactions. Common insects that bite include mosquitoes, bedbugs, fleas, chiggers, and ticks.³ Venomous insects sting with the introduction of venom into people and also cause local irritation and allergic reactions. Common insects that sting include wasps, bees, and ants.³ 

Wasps and bees usually are encountered in a rural setting. They are most abundant during the summer months when flowers are in bloom due to pollen and nectar. Bees and wasps sting humans when provoked or their hives/combs are disturbed.⁴ Visually, bees appear hairy. Bumble bees have yellow, orange, or white stripes on the thorax and abdomen³; on the other hand, honey bees are uniformly dark brown in color.³ Honey bees have barbed stingers with an attached venom sac located at the end of the abdomen. In honey bee workers, the stinger has large, backward-facing barbs on the lancets. When the worker bee stings, the barbs dig into the flesh. As the bee flies off, the entire stinging apparatus is pulled from the bee’s abdomen and embedded in the skin. The honey bee dies as a result of this abdominal rupture.^1-4

Visually, wasps have a black-yellow or dark brown-yellow color.³ They have no fur and are less able to carry pollen.⁴ Some wasps build their nests in ground holes, clay pots, or bamboo stem cavities; others build their nests in tree branches or attics. They have a carnivorous nature.⁴ Unlike honey bees, wasps lack barbs on their stingers; thus, the stingers of wasps will not be removed from their body post sting. Rather, their stingers are usually retracted upon stinging and wasps can sting their prey repeatedly. There’s a high risk to humans when encountered by a swarm of wasps due to their ability to sting more than once.  

Following a bee or wasp sting, about 80% of individuals will have pain, erythema, swelling, and itchiness at the affected site.⁴ Large areas of erythema, itching, and swelling mimicking cellulitis may occur.³ Less commonly, vesicular or bullous lesions and papular urticaria may also occur.³ In addition to local reactions, systemic reactions may rarely occur, which include angioedema, abdominal pain with vomiting, dizziness, laryngeal edema, bronchospasm, hypotension, rhabdomyolysis, acute kidney injury, cardiac arrhythmias, myocardial infarction, ischemic stroke, optic neuropathy, acute transverse myelitis, and anaphylaxis.^5-10 Biphasic reactions have been reported in 1% to 5% of patients after a bee or wasp sting.⁴

First aid management of bee stings includes careful removal of the sting by scraping it out (such as with nail clippers). Removal of the stinger by plucking is not advised because it may push more venom into the affected area. Swelling, itchiness, pain, or local allergy can be relieved by cold compress or ice pack, nonsteroidal anti-inflammatory drugs (ibuprofen), topical antipruritics (such as camphor and menthol), and, if necessary, oral antihistamines and topical corticosteroids. Urgent medical attention should be sought if severe allergic reaction occurs, and subcutaneous epinephrine should be given. If symptoms do not resolve within 2 hours, a second injection of epinephrine is necessary.⁴ Most patients with systemic anaphylactic reactions to bee and wasp stings need venom-specific immunotherapy to protect them from further, potentially life-threatening reactions.^4,9 Physicians must be aware of noxious and venomous creatures in their locality in order to provide accurate diagnosis and timely treatment.¹¹

Paradoxically, anti-inflammatory mechanisms and potential therapeutic applications of components of bee venom have been investigated. In a mouse model, Lee et al¹² demonstrated bee venom significantly reduced the amount of intercellular adhesion molecule 1, vascular cell adhesion molecule 1, transforming growth factor beta 1, and fibronectin in the aorta. A similar pattern was also observed in the heart. The authors concluded that the bee venom has anti-atherogenic properties via its lipid-lowering and anti-inflammatory mechanisms.¹² The anti-inflammatory action also was demonstrated in a rat model.¹³ Peptide 401, from the venom of the bee Apis mellifera L, was shown to be a potent mast cell degranulating factor. Peptide 401 may exert its anti-inflammatory action directly by making the vascular endothelium anergic to phlogistic stimuli.

In a systematic review of randomized controlled trials (RCTs) on bee venom acupuncture for rheumatoid arthritis, Lee et al¹⁴ identified 304 potentially relevant studies, but only 1 RCT¹⁵ met inclusion criteria. Compared with placebo, bee venom acupuncture more effectively improved joint pain, swollen joint counts, tender joint counts, erythrocyte sedimentation rate, and C-reactive protein but was not shown to improve morning stiffness.¹⁴ The authors concluded based on 1 trial that there is low-quality evidence that bee venom acupuncture can significantly reduce pain, morning stiffness, tender joint counts, and swollen joint counts as well as improve the quality of life of patients with rheumatoid arthritis compared with placebo (normal saline injection) control. However, the number of trials, their quality, and the total sample size were too low to draw firm conclusions.¹⁴

In this case report, the authors present a simple method of confirming the diagnosis of insect stings. After the tiny stinger was removed gently with nail clippers and examined microscopically at 80x magnification, the authors were able to confirm the diagnosis of a bee sting rather than that of a wasp or other insect. Physicians should remember to not remove the stinger by plucking due to potentially releasing more venom into the skin. They should also be aware of noxious and venomous creatures in their locality in order to provide an accurate diagnosis and timely treatment for their patients. 

Affiliations: Chinese University of Hong Kong, Hong Kong, China; University of Calgary, Calgary, Alberta, Canada; and Alberta Children’s Hospital, Calgary, Alberta, Canada

Correspondence:
Kam Lun Hon, MD 
The Chinese University of Hong Kong 
Department of Paediatrics
The Chinese University of Hong Kong
6/F, Prince of Wales Hospital
Shatin, New Territories
Hong Kong, China
ehon@hotmail.com 

Disclosure: The authors disclose no financial or other conflicts of interest.