🦠microbiology review

Wheal

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

A wheal is a raised, itchy area of skin that is often a sign of an allergic reaction or infection. It typically resolves within a few hours to days.

5 Must Know Facts For Your Next Test

  1. Wheals are commonly associated with conditions such as urticaria (hives) and allergic reactions.
  2. They are characterized by their transient nature, often appearing and disappearing quickly.
  3. Histamine release from mast cells plays a key role in the formation of wheals.
  4. Wheals can be triggered by insect bites, infections, or contact with allergens.
  5. They may appear alongside other symptoms such as redness, warmth, and swelling.

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