Another name for hives. Raised, itchy areas of skin that are usually a sign of an allergic reaction. Hives can be rounded or flat-topped but are always elevated above the surrounding skin. They reflect circumscribed dermal edema (local swelling of the skin). The hives are usually well circumscribed but may be coalescent and will blanch with pressure.
The hives typically last less than 4 hours but an individual lesion may last for up to 24 hours and the whole process may stay for days or weeks. Approximately 20% of the population has experienced a bout of urticaria.
- Urticaria pigmentosa
The most common form of mastocytosis consisting of small aggregations of mast cells within characteristic salmon-brown patches of skin which itch when stroked and mat develop a localized hive. The condition occurs occurring primarily in children and clears spontaneously with adolescence.
- U.S. National Library of Medicine (NLM)
The world’s largest medical library, the U.S. National Library of Medicine (NLM) is part of the National Institutes of Health (NIH). The NLM has as its mission to collect, organize, and make available biomedical science information to investigators, educators, and practitioners and carry out programs designed to strengthen medical library services in the United States. […]
- U (uracil)
A nucleotide base and one member of the A-U (adenine-uracil) base pair in RNA. The other base pair in RNA is G-C (guanine-cytosine). Uracil takes the place in RNA that thymine (T) occupies in DNA.
- Usher syndrome
The most common disease that diminishes both hearing and vision, a group of genetic disorders in which retinitis pigmentosa (an eye disease that causes vision to deteriorate over time) is combined with congenital deafness. The hearing loss in a patient with Usher syndrome occurs in both ears as a result of nerve deafness. Some patients […]
United States Pharmacopeia.