Measles (known also as RUBEOLA and MORBILLI) is one of the group of blood diseases termed Exanthemata (q.v.), although, from the eruption which appears on the surface of the body, it is sometimes classed with the skin diseases. It is communicable from person to person, not least so in the early stage when it is indistinguishable from an ordinary cold; and it seldom occurs more than once in the same individual. Its period of incubation—i.e. the time that elapses between exposure to the contagion and the first appearance of the febrile symptoms which precede the eruption—is usually about a fortnight; then come lassitude and shivering, which are soon followed by heat of skin, increased rapidity of the pulse, loss of appetite, and thirst. The respiratory mucous membrane is also affected, and the symptoms are very much the same as those of a severe cold in the head, accompanied by a dry cough, a slight sore throat, redness and watering of the eyes, and sometimes tightness of the chest.
The eruption which is characteristic of the disease usually appears upon the fourth day from the commencement of the febrile symptoms and the catarrh—seldom earlier, but occasionally some days later. It is a rash, consisting at first of red papules of various sizes, which, as they multiply, coalesce into crescentic patches. It is two or three days in coming out, beginning on the face and neck, and gradually travelling downwards. The rash fades in the same order as it appears; and, as it begins to decline three days after its appearance, its whole duration is about a week. The red colour gives way to a somewhat yellowish tint, and the cuticle crumbles away in a fine bran-like powder, the process being often attended with itching.
There are two important points in which it differs from Smallpox (q.v.), with which in its early stage it may be confounded; these are: (1) that the fever does not cease or even abate when the eruption appears, but sometimes increases in intensity; and (2) that the disease is not more severe or more dangerous because the eruption is plentiful or early. The character of the eruption, after the first day, will serve to remove all doubt regarding these two diseases; and the comparative prevalence of either disease in the neighbourhood will materially assist in forming the diagnosis. It is distinguished from Scarlet Fever (q.v.) or scarlatina (1) by the presence at the outset of catarrhal symptoms, which do not occur in the latter disease, at any rate prior to the eruption; (2) by the absence of the characteristic throat-affection, which always accompanies well-marked cases of scarlet fever; (3) by the character of the rash, which in measles is said to present somewhat the tint of the raspberry, and in scarlet fever that of a boiled lobster; which in measles appears in crescentic patches, and in scarlet fever is universally diffused over the parts affected; which in measles usually appears on the fourth day, and in scarlet fever on the second day of the disease.
In ordinary uncomplicated measles, the prognosis is almost always favourable. The chief danger is from inflammation of some of the textures that compose the lungs; and in scrofulous children it often leaves chronic pulmonary mischief behind it. No age is exempt from the disease, but it is much more common in childhood than subsequently. The reason probably is that most persons have it in early life, and are thus protected from an attack at a later period.
In mild forms of the disease, nothing more is requisite than to keep the patient on a low diet, attend to the state of the bowels, and prevent exposure to cold, which is best accomplished by keeping him in bed with the ordinary warmth to which he is accustomed in health. While the eyes are red and irritable, it is desirable that he should be shaded from the light. If the chest-symptoms become urgent, they must be treated according to their nature. Bronchitis (q.v.), sometimes extending into Pneumonia (q.v.), is most to be feared. If the eruption disappear prematurely, it may sometimes be brought back by placing the patient in a warm bath. In such cases stimulants are often required, but must, of course, only be given by the advice of the physician. The patient must be carefully protected from exposure to cold for a week or two after the disease has apparently disappeared, as the lungs and mucous coat of the bowels are for some time very susceptible to inflammatory attacks. In some cases considerable debility remains for a long time after the attack; and both the eyes and ears are very liable to injury from inflammations accompanying or succeeding it.
German Measles is a name somewhat loosely used of a disease, or possibly several diseases, resembling measles, but for the most part less prolonged and severe. The cases grouped under this title, however, require further elucidation, as descriptions given by different authors differ very widely from each other.