Polymorphic light eruption is a common skin reaction to sunlight that occurs most commonly in people with fair skin. Polymorphic light eruption results in small red raised spots and blisters on the skin within four days after exposure to ultraviolet radiation, such as from sunlight. The term polymorphic means that the skin reaction may take many different forms, although the small raised red lesions are most typical (for example, itchy, small bumps on the skin). Polymorphic light eruption is most common on the arms, but the legs and chest may also be affected. Involvement of the face is rare. Polymorphic light eruption is also termed polymorphous light eruption.
A variation in the DNA that is too common to be due merely to new mutation. A polymorphism must have a frequency of at least 1% in the population. Examples of polymorphisms include the genes for sickle cell disease, thalassemia and G6PD deficiency. These genes are widely believed to offer an advantage against malaria.
- Polymorphonuclear leukocyte
A type of white blood cell with a nucleus that is so deeply lobated or divided that the cell looks to have multiple nuclei. Informally called a poly.
Pain in multiple muscles, as in polymyalgia rheumatica.
- Polymyalgia rheumatica (PMR)
A disorder of the muscles and joints of older persons characterized by pain and stiffness, affecting both sides of the body, and involving the shoulders, arms, neck, and buttock areas.