What Are Hives?
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Raised red skin welts usually triggered by direct contact with allergen by Plato 18 year
Urticaria or hives is a relatively common form of allergic reaction that is characterized by raised red skin welts. Urticaria is also known as nettle rash or uredo. These welts can range in diameter from 5 mm (0.2 inches) to 25mm (1 inch). These welts can itch severely, and often have a pale border.
Urticaria is generally triggered by direct contact with an allergenic substance, or an immune response to food or by contact with some other allergen. Stress is an important factor in Hives and can trigger Hives.
Angioedema is a related condition where similar types of swelling occur in a lower layer of the skin, mouth or throat. It is not identical to urticaria. They may, however, occur together.
The rash derived from poison-ivy is commonly mistaken for urticaria. Poison-ivy is caused by urushiol toxin. This resin can be spread by contact, but it is easily washed off.
Types
Acute urticaria usually show up a few minutes after contact with the allergen and can last a few hours to several weeks. Food allergic reactions typically fit in this category.
Common causes of reaction include consumption of shell fish, nuts, eggs, fish, acid derivitives, dye.
Chronic urticaria refers to hives that persists for 6 weeks or more. There are no visual differences between acute and chronic urticaria. Some of the more severe chronic cases have lasted more than 20 years.
Drug-induced urticaria has been known to result in severe cardiorespiratory failure. The anti-diabetic suphonylurea glimepiride (trade name Amaryl®), in particular, has been documented to induce allergic reactions manifesting as urticaria. Other cases include aspirin, penicillin, sulfonamides and anticonvulsants.
Physical urticarias is often categorized into the following:
Aquagenic: Reaction to water (rare)
Cholinergic: Reaction to body heat, such as when exercising or after a hot shower
Cold: Reaction to cold, such as ice, cold air or water
Delayed Pressure: Reaction to standing for long periods, bra-straps, belts
Dermographism: Reaction when skin is scratched (very common)
Heat: Reaction to hot food or objects (rare)
Solar: Reaction to direct sunlight (rare)
Vibration: Reaction to vibration (rare)
Adrenergic: Reaction to adrenaline / noradrenalin (extremely rare)
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Urticaria or hives is a relatively common form of allergic reaction that is characterized by raised red skin welts. Urticaria is also known as nettle rash or uredo. These welts can range in diameter from 5 mm (0.2 inches) to 25mm (1 inch). These welts can itch severely, and often have a pale border.
Urticaria is generally triggered by direct contact with an allergenic substance, or an immune response to food or by contact with some other allergen. Stress is an important factor in Hives and can trigger Hives.
Angioedema is a related condition where similar types of swelling occur in a lower layer of the skin, mouth or throat. It is not identical to urticaria. They may, however, occur together.
The rash derived from poison-ivy is commonly mistaken for urticaria. Poison-ivy is caused by urushiol toxin. This resin can be spread by contact, but it is easily washed off.
Types
Acute urticaria usually show up a few minutes after contact with the allergen and can last a few hours to several weeks. Food allergic reactions typically fit in this category.
Common causes of reaction include consumption of shell fish, nuts, eggs, fish, acid derivitives, dye.
Chronic urticaria refers to hives that persists for 6 weeks or more. There are no visual differences between acute and chronic urticaria. Some of the more severe chronic cases have lasted more than 20 years.
Drug-induced urticaria has been known to result in severe cardiorespiratory failure. The anti-diabetic suphonylurea glimepiride (trade name Amaryl®), in particular, has been documented to induce allergic reactions manifesting as urticaria. Other cases include aspirin, penicillin, sulfonamides and anticonvulsants.
Physical urticarias is often categorized into the following:
Aquagenic: Reaction to water (rare)
Cholinergic: Reaction to body heat, such as when exercising or after a hot shower
Cold: Reaction to cold, such as ice, cold air or water
Delayed Pressure: Reaction to standing for long periods, bra-straps, belts
Dermographism: Reaction when skin is scratched (very common)
Heat: Reaction to hot food or objects (rare)
Solar: Reaction to direct sunlight (rare)
Vibration: Reaction to vibration (rare)
Adrenergic: Reaction to adrenaline / noradrenalin (extremely rare)
Viewed 8729 times
All Plato's Answers