# Hymenoptera Sting and Spider Bite

> Hymenoptera sting and spider bite for NEET-PG Medicine, covering bee and wasp envenomation, anaphylaxis, and black widow and brown recluse features.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/hymenoptera-sting-and-spider-bite
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Harrison's Principles of Internal Medicine; Goldfrank's Toxicologic Emergencies
- How to cite: "Hymenoptera Sting and Spider Bite", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/hymenoptera-sting-and-spider-bite

## Direct answer

A hymenoptera sting from a bee, wasp or hornet causes local pain and swelling in most people, but anaphylaxis is the dangerous outcome. Spider bites are less often serious, although the black widow causes systemic neurotoxicity and the brown recluse causes local necrosis. Management centres on removing the sting, giving intramuscular adrenaline for anaphylaxis and supportive care, with antivenom reserved for severe envenomation.

## What you must remember

- **Local reaction:** pain, swelling and redness around the sting that peak within a day or two and settle, without systemic features.
- **Anaphylaxis:** urticaria, angioedema, bronchospasm and hypotension within minutes to an hour of the sting; adrenaline is the first-line drug, usually 0.5 mg intramuscularly in adults.
- **Stinger removal:** scrape a honeybee stinger off with a fingernail or blunt edge rather than squeezing, since squeezing injects more venom; wasps usually leave no stinger.
- **Adjuncts:** antihistamines and corticosteroids help the skin and delayed symptoms but do not replace adrenaline in airway or circulatory compromise.
- **Black widow (Latrodectus):** latrotoxin causes severe pain, muscle cramps, sweating, hypertension and a rigid abdomen that can mimic an acute abdomen.
- **Brown recluse (Loxosceles):** local necrosis that evolves over days into an ulcer, with systemic haemolysis and DIC being rare.
- **Venom immunotherapy:** offered to selected patients who have had a systemic reaction to a hymenoptera sting, after specialist assessment.
- **Indian context:** snakebite and scorpion sting dominate envenomation caseloads, while bee and wasp stings are common in rural and forest areas.

## Hymenoptera stings and spider bites compared

Hymenoptera and spider envenomation share one emergency pattern: local signs are common, but the systemic reaction decides the outcome.

| Feature | Hymenoptera sting | Black widow | Brown recluse |
|---|---|---|---|
| Source | Bees, wasps, hornets | Latrodectus spiders | Loxosceles spiders |
| Main effect | Local pain and anaphylaxis | Neurotoxic cramps and autonomic upset | Local necrotic ulcer |
| Systemic picture | Urticaria, bronchospasm, hypotension | Rigid abdomen, sweating, hypertension | Rarely haemolysis or DIC |
| Key treatment | Adrenaline for anaphylaxis | Analgesia, benzodiazepines, antivenom in severe cases | Wound care; antivenom role debated |

Anaphylaxis is the only sting outcome that is immediately life-threatening, so the airway and blood pressure are checked before wound care. Spider bites usually produce a local lesion, but the systemic picture of a black widow envenomation can mimic an acute abdomen, which is a favourite exam trap.

Patients who have had anaphylaxis need observation, because a biphasic reaction can recur hours after the first episode. Spider bites are rarely confirmed by seeing the spider, so the clinical course and the shape of the lesion carry most of the diagnostic weight.

## Where the exam tries to catch you

Most lost marks come from treating every sting as a local wound or every spider bite as a necrotic ulcer.

- **Trap:** squeezing a honeybee sting to remove the venom sac — **Correct:** scrape the stinger off with a flat edge, since squeezing injects more venom.
- **Trap:** giving antihistamines alone for a sting with wheezing and hypotension — **Correct:** this is anaphylaxis; give intramuscular adrenaline first, with antihistamines as adjuncts.
- **Trap:** diagnosing a brown recluse bite from any painful skin lesion — **Correct:** the diagnosis is clinical, and necrosis evolving over days is the cue, not pain alone.
- **Trap:** attributing a rigid abdomen with hypertension to appendicitis without a history — **Correct:** black widow envenomation mimics an acute abdomen, so ask about spider exposure and muscle cramps.

## Frequently asked questions

### What is the first-line treatment for anaphylaxis after a bee sting?

Intramuscular adrenaline is the first-line treatment for anaphylaxis after a bee or wasp sting, given into the anterolateral thigh without waiting for other drugs. Antihistamines and corticosteroids are adjuncts and do not replace adrenaline in a patient with airway or circulatory compromise.

### How should a honeybee sting be removed?

A honeybee sting should be removed by scraping the stinger off with a fingernail or blunt edge rather than squeezing the venom sac. Squeezing can inject more venom, whereas wasps usually leave no stinger behind.

### Which spider bite causes systemic neurotoxicity?

The black widow spider, of the genus Latrodectus, causes systemic neurotoxicity through latrotoxin, producing severe pain, muscle cramps, sweating and a rigid abdomen. Opioid analgesia and benzodiazepines relieve the cramps, antivenom is reserved for severe cases (intravenous calcium gluconate is now of doubtful benefit), and the picture can mimic an acute abdomen.

### What local lesion is typical of brown recluse bites?

Brown recluse bites, from the genus Loxosceles, cause local dermonecrosis that evolves over days into a necrotic ulcer. Systemic features such as haemolysis are rare, and the role of antivenom remains debated, so wound care is the mainstay.

### Why do venom-allergic patients need specialist review?

Patients with a previous systemic reaction to a hymenoptera sting should be referred for specialist assessment and considered for venom immunotherapy. This treatment reduces the risk of a future anaphylactic reaction and is offered to selected patients only.