Knowra Hives Hives Hives are raised, itchy welts that appear when fluid leaks from small blood vessels into the skin. Individual welts often change shape or location and usually fade within 24 hours.
Mast cell : A tissue-resident immune cell that releases histamine and other chemical mediators. Mast-cell activation commonly releases the mediators that produce hives.
Urticaria : A skin condition characterized by transient wheals, angioedema, or both. Urticaria is the medical name for the condition commonly called hives.
Chronic spontaneous urticaria : Urticaria occurring repeatedly for more than six weeks without a consistent external trigger. It is a persistent pattern in which hives arise without an identifiable immediate cause.
Eczema : A group of inflammatory skin disorders often causing persistent dryness, redness, and itch. Eczema patches usually last longer than individual hives and may become scaly.
Second-generation antihistamine : A newer H1-receptor-blocking medicine with less sedation than older antihistamines. These medicines are commonly used as first-line treatment for uncomplicated hives.
Histamine : A signaling molecule involved in immune responses, stomach acid secretion, and neurotransmission. Histamine widens small blood vessels and increases their permeability, producing itchy welts.
Pruritus : An unpleasant sensation that provokes the desire to scratch. Itching is a defining symptom, distinct from the visible swelling itself.
Cold urticaria : An inducible urticaria triggered by exposure to cold air, water, or objects. Cold exposure can provoke welts and, in some cases, systemic reactions.
Contact dermatitis : Skin inflammation caused by direct contact with an irritating or allergenic substance. Its rash generally remains at contact sites rather than migrating like hives.
Omalizumab : A monoclonal antibody that binds immunoglobulin E and is used for selected allergic and urticaria conditions. It can treat chronic spontaneous urticaria that remains uncontrolled with antihistamines.
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