In perhaps more than 50% of people with chronic hives of unknown cause, it is due to an autoimmune reaction. Many different substances in the environment may cause hives, including medications, food and physical agents. Hives can also be classified by the purported causative agent. Hives caused by stroking the skin (often linear in appearance) are due to a benign condition called dermatographic urticaria. Individual hives that are painful, last more than 24 hours, or leave a bruise as they heal are more likely to be a more serious condition called urticarial vasculitis. Īngioedema is a related condition (also from allergic and nonallergic causes), though fluid leakage is from much deeper blood vessels in the subcutaneous or submucosal layers. In half of cases of hives, the cause remains unknown. Fewer than 5% of cases last for more than six weeks. Cases of short duration are more common among children while cases of long duration are more common among those who are middle aged. Cases of long duration are more common in females. Cases of short duration occur equally in males and females, lasting a few days and without leaving any long-lasting skin changes. Welts may be pinpoint in size or several inches in diameter.
Whether the trigger is allergic or not, a complex release of inflammatory mediators, including histamine from cutaneous mast cells, results in fluid leakage from superficial blood vessels. Welts (raised areas surrounded by a red base) from hives can appear anywhere on the surface of the skin. Hives, or urticaria, is a form of skin rash with red, raised, itchy bumps. The term urticaria is from the Latin urtica meaning " nettle". Hives have been described at least since the time of Hippocrates.
Cases of short duration occur equally in males and females while cases of long duration are more common in females. For cases that last more than six weeks immunosuppressants such as ciclosporin may be used. Keeping the environmental temperature cool is also useful. In severe cases, corticosteroids or leukotriene inhibitors may also be used. Treatment is typically with antihistamines such as diphenhydramine and ranitidine. Prevention is by avoiding whatever it is that causes the condition.
#Tiny pinpoint red dots on skin not itchy Patch
Patch testing may be useful to determine the allergy. Diagnosis is typically based on the appearance. Risk factors include having conditions such as hay fever or asthma. In half of cases the cause remains unknown. Psychological stress, cold temperature, or vibration may also be a trigger. Hives frequently occur following an infection or as a result of an allergic reaction such as to medication, insect bites, or food. The patches of rash may appear on different body parts, with variable duration from minutes to days, and does not leave any long-lasting skin change. Hives, also known as urticaria, is a kind of skin rash with red, raised, itchy bumps. Dermatology, Clinical immunology, Allergologyįollowing an infection, result of an allergic reaction Īntihistamines, corticosteroids, leukotriene inhibitors
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