The pre-eruptive illness of measles.

According to Sydenham (1717), the rash of measles appears on the fourth, or sometimes the fifth, day of the illness. This has remained the standard teaching of most of the authorities on infectious diseases and paediatrics (e.g. Sheldon, 1948; Banks, 1949; Harries and Mitman, 1951; Top, 1955). However, Panum (1847), in his classic report of a measles epidemic, states that although the prodromal illness usually lasts two to four days it can last up to eight days. Some modern writers agree and allow that on occasion the prodromal illness may be as long as six to eight days (e.g. Joe, 1947; Stimson and Hodes, 1956; Ellis, 1956). Recently Christensen, Schmidt, Bang, Andersen, Jordal and Jensen (1953), observing a very similar epidemic in Southern Greenland to that described by Panum in the Faroe Islands, also found that the prodromal illness may be as long as eight days. Two cases with a prodromal illness lasting nine and 11 days respectively were recorded by Selby (1936), and Spence, Walton, Miller and Court (1954), in their 1,000-family survey, found two patients who were ill throughout the incubation period. A relatively unknown feature of the pre-eruptive period of measles is the 'illness of infection', first described by Goodall (1925). Despite at least 25 cases reported in the literature (Erdheim, 1926; Abercrombie, 1929; Meyer and Greenthal, 1930; Smith, 1944), and a reasonable theoretical basis (Grist, 1950), it has received scant attention.