SYMPTOMS AND COURSE.—As already stated, the probable average duration of the incubation period in rötheln is about fourteen days, varying, however, within the limits of from six to twenty-one days. In this respect rötheln resembles scarlatina more than measles, the period of latency in the latter observing considerable uniformity. No deviations from the general health are to be noted in the incubation stage.
In most cases prodromal symptoms are entirely absent, the presence of the eruption being the first thing to show the existence of rötheln in the system. On the other hand, in a certain proportion of cases there will be present for a half day, or even longer, the general symptoms of malaise, such as slight nausea, some sore throat, pain in the limbs, stiffness of the neck, etc. Vomiting is generally absent. J. L. Smith records one case of convulsions in the stage of invasion, and I have notes of a single case in which the prodromal stage was initiated by mild delirium and fever, the latter anticipating the eruption for two days and a half, and disappearing when the rash came out. As Thomas well observes, however, such cases are anomalous, and indicate either abnormal sensibility on the part of the patient or are due to a secondary rötheln.
Most observers (Emminghaus, Thomas, Smith, Squire) describe the rash as coming out in the order usual in measles—namely, first upon the face, scalp, and neck, then the trunk and arms, and finally the legs. Others (Liveing, Morris) have stated that the rash first appears upon the back and chest. In many cases in my own experience this has seemed to be true. It is quite probable that the situation of the exanthem in rötheln, as in measles and scarlatina, may present various irregularities; but I am inclined to believe that a careful investigation will in most instances show that the normal course of the eruption is as first stated. Now, a marked characteristic of the rash of rötheln is that, unlike that of measles, there is no period, however short, in which its maximum is simultaneous over the whole body; on the contrary, the eruption will have reached its full development upon the face, and will be almost or quite faded again, before the exanthem, for example, will have blossomed upon the trunk, and especially upon the lower extremities. The duration of the eruption upon individual parts of the body is probably from a few hours to half a day at most (Thomas). A consideration of these facts explains, according to Emminghaus, how different observers have described the eruption as having its seat upon this or that region of the body; in other words, it is probable that in a certain proportion of the cases in which the rash was supposed to have begun on the chest it had already run its course upon the face. The eruption usually continues altogether about four days, sometimes disappearing sooner, and sometimes being visible, especially as a fine mottling, for some days longer. So far as the individual lesions of the eruption are concerned, there is no question that they present, within a certain range, varying aspects; and this clinical fact has been taken advantage of by the opponents of the idea of specificity in order to make it appear that the disease is not sui generis, inasmuch as it lacks uniformity of expression. Such an argument wants force when we consider that in making up a given diagnosis we lay stress not upon special, but upon the ensemble of, symptoms. For example, no one would deny to measles an independent position because the eruption, as is well known, may assume this or that form (morbilli lævis, m. papulosi, etc.); on the contrary, we recognize a particular case or series of cases to be measles from a due appreciation of all the symptoms present. So it is to be expected that while the cutaneous lesions will present a certain similarity of feature, as they do, there will also exist minor differences in detail.
In the greatest number of cases in my own experience the exanthem is composed of ill-defined, roundish, punctate macules, without special grouping. These are usually discrete, but in certain situations they may coalesce. The color is of a pale rosy red, quite difficult to describe, but less purplish than in measles, and not so livid a red as in scarlatina. I have occasionally observed large irregular spots not unlike those of measles.7
7 According to Emminghaus (op. cit., p. 345), the eruption generally forms roseolæ of pin-head, lentil, or small bean size. They are mostly round, sometimes oval, and bordered by well-defined or by blurred edges. The intervening skin is not always unchanged, for here and there we find upon it small dilated blood-vessels, and from the spots processes extend with a certain regularity to other spots in such a way as to give the skin a marbled appearance.
Thomas distinguishes three types of eruption—one with large spots, which is rare; one with medium-sized spots; and one with small spots. Emminghaus describes a discrete and a more confluent variety. I have observed one case where the maculæ on the back had undergone a vesicular transformation. Others have mentioned this occurrence. Itching of the skin is marked in some cases, and a fine desquamation is observed after the rash, but by no means invariably.
The mucous membranes are implicated to a slight degree in rötheln, but the amount of involvement varies considerably. In some cases that I have observed the catarrh of the mucous membranes has been barely appreciable. As a rule, however, the eyes are somewhat suffused, and there is slight lachrymation and photophobia. Sneezing may be noted, but there is little discharge from the nose. Sore throat is not uncommon, perhaps the most constant feature, and, according to Liveing, is apt to persist after the subsidence of the rash. The fauces are injected, and the tonsils are red and swollen, but with no evidence of ulceration. J. Lewis Smith and others state that the buccal mucous membrane shows a more or less diffuse patchy and spotted redness. The tongue may be, and usually is, covered by a white fur, through which protrude a few enlarged red papillæ. There may be slight cough. Loeri8 describes the mucous membranes of the pharynx, larynx, and trachea as presenting a spotted or uniform hyperæmia. There is no marked participation of the intestines in the catarrh. Some few writers have noted a transient albuminuria, but it is safe to say that such cases are entirely anomalous, if not, indeed, in some instances, examples of mistaken diagnosis.
8 Jahrb. f. Kinderk., xix. Bd., 1 Heft.
A very constant feature is the swelling of the lymphatic glands of the neck, especially those back of the sterno-mastoid; the swellings may come on before the rash appears. In all the cases that have fallen under my notice this symptom has not been absent in a single instance. Less constantly, and it would seem in proportion to the development of the rash, engorgement of the glands may be noted elsewhere.
There is but slight disturbance of the temperature in rötheln, and when it does occur it is usually limited to the first few hours of the eruption. This has been the rule in my observation, and certainly holds good for the majority of cases. In a minority, varying degrees of fever may be present; thus, the temperature may reach 102° F. or 103° F., and then rapidly sink by the second day of the disease, or, having fallen a degree, it may continue at this point till the subsidence of the rash, or, it is said, may retain its initial height till the end of the disease. During the following week Squire states that the temperature may be readily disturbed—either elevated by exertion or depressed by fatigue or chill. A relapse or recrudescence of the rash may be looked for at this time.9