Wheal

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.

Review Questions

• What causes the formation of a wheal?
• How long do wheals typically last on the skin?
• Name two common triggers for the development of wheals.

Related terms

Urticaria: A skin condition characterized by the sudden appearance of wheals or hives.

Histamine: A compound involved in local immune responses, leading to symptoms such as itching and swelling.

Mast Cells: Cells found in connective tissue that release histamine during inflammatory and allergic reactions.