The eruption of measles like any other erythema causes great dif ficulty in diagnosis when it is less well defined and rudimentary in char acter, and not accompanied by fever. The dIfferentiation from well marked German measles, more than anything else, proves an obstacle to diagnosis which from a clinical standpoint cannot be absolutely obviated. These can only surely be distinguished early in the case when on the one hand the Koplik spots, and on the other, the small round spots typical of the early German measles can solve the problem as to diagnosis. The more intense forms of measles rash can lead to confusion with other erythemata. I have met with one such case in which there was marked infiltration of the individual spots, they were of a nodular form, livid red in appearance, and particularly as they stood in thick groups together, several of my colleagues made the (hag nosis of variola. A glance into the mouth suffices as a rule to correct the error, quite apart from the other points of diagnosis (in measles, the preceding catarrhal signs, and the intense redness of the spots, in variola, a less thickly set papular eruption, oftentimes leaving the abdomen free, and with an early outbreak of pox upon the face, etc).
From scarlet fever the initial symptoms of measles are distinguished by the greater affection of the alimentary tract in the former, the greater angina, and the form of the rash. The region of the lips and chin is regularly free from rash in scarlet fever. An error in regard to scarlet fever can arise with the so-called confluent measles, yet in the general grouping together of all the symptoms, and the scrutiny of all the parts affected by the rash one will soon find some point or another character istic of measles. Measles and scarlet fever may however occur together, and then they form a difficult diagnostic puzzle.
Serum rashes must be mentioned in conjunction with that of measles as they can show a great similarity in the skin and mucous membranes. The absence of the Koplik spots, the irregularity in the outbreak of the rash, also the sequence in which the several parts of the skin are affected, and above all the fact of the injection of the serum, will overcome the difficulty as to diagnosis. I have twice seen intense large typhoid roseola spots which had a great similarity to measles.
Difficulty may perhaps also arise with the maculopapular erup tions which occur with the gastro-intestinal disturbances of nursing infants, especially when they break out with great severity. These are intensely red, sharply defined, and quite isolated spots about the size of a bean; they occur mostly on the extremities, and are, like many artifi cially produced erythemata, characterized by the absence of any change whatsoever in the mucous membranes. Infectious erythema (see Plate 1s) as well as erythema multi forme, is characterized by its diverse gyrate outline, its pale central portions, its localized occurrence espe cially upon the extensor surfaces of the extremities. A confusion of tuticarial with measles, is easily avoided.
Prognosis.—This is usually good in strong healthy persons living in good hygienic conditions, even if the attack be severe and the gen eral condition much affected. When the rash fades rapidly it is a threat ening sign; this applies to the adult, but still more so to the child. The mortality in private practice is very small. In Heubner's polyclinic in Leipzig it was 3.1 per cent. Jurgensen in Tubingen gives an average of 6.1 per cent for 20 years. The mortality rates in hospitals alone arc not to be compared, as here the death rate is frightfully high, and in many instances exceeds 30 per cent. This is not to be wondered at when one considers that only the poorest people send their children with measles to the hospital. These poorly nourished, anaemic and oftentimes tuberculous children, form with those already in the hos pital, and secondarily affected with measles, the sure prey of death. That form designated as "Septic Measles" always leads to a fatal issue. By reason of the frequency of complications in the respiratory tract, children under one year of age furnish the greatest mortality. In one epidemic, Henoch gives the mortality rate under two years of age as 55* per cent.
Those rare measles rashes which break out with very high fever and severe general symptoms in the early stages, and which are often recognized only with difficulty, are unfavorable from a prognostic stand point. The livid or brownish discoloration of the rash is to be interpreted as pointing to the onset of heart or lung complications, and is likewise unfavorable. Again, as to prognosis, as was formerly pointed out, the temperature is worthy of note when it does not fall to normal as the rash fades; this generally signifies the advent of complications. Of all the complications that can occur, mixed infection with diphtheria or influenza is the most unfavorable, as it appears that those infected with measles show a very much lowered resistance by reason of the lessened production of antibodies. A most frequent and unfavorable effect re sults from the advent of severe bronchitis and foci of pneumonia, and in consequence of existing or subsequent tuberculosis in predisposed individuals, likewise in rachitic, amemic and weakly children, particular caution is enjoined in predicting the further course of the disease. The tuberculous lesions mostly arise after an interval of weeks or months of apparent well-being. Likewise one finds an increase of the hemorrhagic diathesis in those formerly predisposed to it. While purpuric condi tions following measles arc seldom of unfavorable prognosis, htemo philiacs show during measles grave progress in their constitutional anomaly. We may be easily enticed into an unfavorable judgment of the course of the disease by the condition of the nervous system, as by convulsions, delirium and stupor. These in all their severity, so long as they do not last many days, are of no permanent harm, as they arc of an evanescent nature, and are not to be interpreted as of bad prognosis.