Insect bite and sting reaction (local and large local reaction)

Synonyms
Insektenstich, Mückenstich, Wespenstich, gesteigerte Lokalreaktion, Insect bite reaction, Insect sting, Large local reaction
Specialty
Dermatology · Environmental & photodermatoses
Images
Clinical 1 · Histology 1
In the app
1 flashcards
Last updated
10/2026 · Dr. Pascal Bafteh
Contents
  1. Images (2)
  2. Definition
  3. Classification
  4. Clinical features
  5. Histology
  6. Diagnosis
  7. Differential diagnoses
  8. Keep learning in the app
  9. References (selection)
  10. Cross-references

Images (2)

Insect bite and sting reaction (local and large local reaction) – leg – clinical photo: Multiple itchy, edematous papules on the shin following horsefly (Tabanidae) bites; edema developing over 5 days
Multiple itchy, edematous papules on the shin following horsefly (Tabanidae) bites; edema developing over 5 days (leg)NiaPol, „Bites of a blood-sucking insect (Tabanidae) 003a", CC BY-SA 4.0, via Wikimedia Commons · CC BY-SA 4.0 · Source
Insect bite and sting reaction (local and large local reaction) – histology (H&E): a largely preserved epidermis with a basket-weave stratum corneum over a superficial and deep perivascular and interstitial infiltrate that extends wedge-shaped into the …Histology
histology (H&E): a largely preserved epidermis with a basket-weave stratum corneum over a superficial and deep perivascular and interstitial infiltrate that extends wedge-shaped into the …Nephron, „Dermal perivascular lymphoeosinophilic infiltrate - high mag", CC BY-SA 3.0, via Wikimedia Commons · CC BY-SA 3.0 · Source
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Definition

A skin reaction to the sting or bite of an insect. Hymenoptera (bees, wasps, hornets) deliver venom in self-defence; blood-feeding insects such as mosquitoes, fleas and bed bugs pierce the skin to feed. This page focuses on local reactions; systemic reactions belong to insect venom allergy.

Classification

  • Normal local reaction (bee, wasp): immediate sharp pain, then redness, swelling, itch; usually resolves within 24 hours.
  • Large local reaction: swelling over 10 cm, peaking at around 48 hours, lasting up to a week, sometimes involving a whole limb. Swelling alone is not a sign of systemic allergy.
  • Systemic reaction, for distinction: urticaria, angioedema, bronchospasm, hypotension.

Clinical features

  • Bites of blood-feeding insects: intensely itchy, often grouped papules on exposed sites, sometimes with a central clear or haemorrhagic blister.
  • Scratching leads to open sores; secondary bacterial infection (impetigo, cellulitis) is possible.
  • Papular urticaria: mostly in young children after flea or mosquito bites, symmetrical itchy papules; new bites reactivate old lesions.
  • Persistent bite reaction: urticarial, bullous, vasculitic or granulomatous for weeks to months.

Histology

Rarely needed; suggestive features are a central punctum, eosinophilic spongiosis and a wedge-shaped mixed infiltrate around the sweat ducts.

Diagnosis

  • Usually clinical from history and appearance; after bee stings the stinger may remain in the skin.
  • Redness and swelling beginning only after one or two days, significant pain or fever point rather to secondary infection.
  • Allergy work-up (prick/intradermal tests, specific IgE) after a systemic reaction; to be considered after a large local reaction.

Differential diagnoses

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References (selection)

  1. DermNet: Arthropod bites and stings
  2. DermNet: Bee and wasp stings
  3. MSD Manual Professional: Insect Stings

Cross-references

Mentioned in

More environmental and photodermatoses

Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases.