<unk>  is caused by a raised body temperature. This may be caused by: * hot weather * exercise * fever * saunas * sun tanning * hot tubs, and hot baths and showers * hot food and drink * menstruation (which may raise body temperature) * sitting near a radiator
Uhthoff's phenomenon
Lucio's phenomenon
Bell's phenomenon
Renbök phenomenon
Kohnstamm's phenomenon
Jod-Basedow phenomenon
Tullio phenomenon
Waddell's signs