Related topics: bees

Stung by drought, Morocco's bees face disaster

Morocco's village of Inzerki is proud to claim it has the world's oldest and largest collective beehive, but instead of buzzing with springtime activity, the colonies have collapsed amid crippling drought.

Bees can tell time by temperature, research finds

Bees are known to tell time by light and social cues. Now, postdoctoral scholar in biological sciences Manuel Giannoni-Guzmán and researchers from Brandeis University, University of Puerto Rico Rio Piedras, University of ...

Honeybees reveal environmental pollution in their surroundings

Honeybee colonies are bioindicators of environmental contamination in the area, since they get coated in everything that there is in the environment, including pollutants, and they end up taking it all back to their bee hives.

Group genomics drive aggression in honey bees

Researchers often study the genomes of individual organisms to try to tease out the relationship between genes and behavior. A new study of Africanized honey bees reveals, however, that the genetic inheritance of individual ...

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Urticaria

Urticaria (from the Latin urtica, nettle (whence It. ortica, Sp. ortiga, Pg. urtiga, Fr. ortie) urere, to burn) (or hives) is a kind of skin rash notable for pale red, raised, itchy bumps. Hives is frequently caused by allergic reactions; however, there are many non-allergic causes. Most cases of hives lasting 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. The majority of patients with chronic hives have an unknown (idiopathic) cause. Perhaps as many as 30–40% of patients with chronic idiopathic urticaria will, in fact, have an autoimmune cause. Acute viral infection is another common cause of acute urticaria (viral exanthem). Less common causes of hives include friction, pressure, temperature extremes, exercise, and sunlight.

Weals (raised areas surrounded by a red base) from urticaria can appear anywhere on the surface of the skin. Whether the trigger is allergic or non-allergic, there is a complex release of inflammatory mediators, including histamine from cutaneous mast cells, resulting in fluid leakage from superficial blood vessels. Wheals may be pinpoint in size, or several inches in diameter. Angioedema is a related condition (also from allergic and non-allergic causes), though fluid leakage is from much deeper blood vessels. 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. Hives caused by stroking the skin (often linear in appearance) are due to a benign condition called dermographism.

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