Contact urticaria (hives)
Skin | Allergy & Immunology | Contact urticaria (hives) (Disease)
Hives (also known as urticaria) is a type of rash that is characterized by circular wheals of reddened and itching skin. The wheals can be diffrent in size, from relatively small to as large as a dinner plate. The condition can afflict any part of the body, but is common to the trunk, throat, arms and legs. The wheals generally rise in clusters, with one cluster getting worse as another gets better.
Symptoms of hives include:
(1) Raised circular wheals appear that look like mosquito bites.
(2) Localized itching is present.
(3) The wheals are red on the outer rim and white in the centre.
(4) One batch fades away as a new batch appears.
(5) The wheals appear in batches or clusters.
(6) An individual weal has a lifespan of around 24 hours or less.
(7) The rash may last for days or weeks.
Causes and Risk factors
Hives are frequently caused by allergic reactions; however, there are also many non-allergic causes. Most cases of hives that last less than six weeks (acute urticaria) are the result of an allergic trigger. Chronic urticaria (hives lasting longer than six weeks) is rarely due to an allergy.
In around one-third of cases, the cause of hives is unknown. Some factors known to cause hives include: foods – such as shellfish, eggs, nuts, peanuts, chocolate, cheese, tomatoes, soy products and strawberries ; medications – such as antibiotics, aspirin and codeine ; some food additives ; infections – including bacterial, viral or parasitic ; certain underlying conditions – such as systemic lupus erythematosus, rubella and hepatitis ; emotional stress ; certain plants ; sunshine and heat ; cold temperatures ; exercise and sweating ; bee and wasp stings.
Diagnosis and Treatment
Treatment for urticaria may include antihistamines, corticosteroids, and additional medications that treat allergic reactions. Treatment in those with allergies may also include allergy shots. ...