In sharp contrast to the toxic form of scarlet fever stands the so called infectious form, in which, in addition to the primary pharyngeal disturbances, there appears on the third to the fifth day of the disease necrosis of the mucous membrane, varying in degree and extent. In these eases the infection extends to the pharynx from the nose and its accessory sinuses (such as the antrum of Highmore), involving later the middle ear, the cervical lymph-nodes, and the lymph-nodes of the lower jaw.
So far as the pharynx and regional lymph-nodes are concerned, the changes noted here are present in all fully developed cases of scarlet fever. They do not in any way invalidate a favorable prognosis, nor do they delay crisis. However, they are apt to be more superficial and reach an early resolution.
In the more severe cases the areas of necrosis appear not only on the surface, but also in the deeper layers of the mucous membrane and often extend as far as the submucosa.
Clinically, the occurrence of these changes is noted, first, in the temperature curve. Instead of the usual morning remission of one or more degrees, noted on the third or fourth day, the temperature falls only a fraction of a degree and the afternoon temperature, which ordi narily exhibits a steady fall, is now seen to rise. Consequently, the char acteristic lysis does not appear.
On inspection, the pharynx is seen to be considerably more swollen, the necrotic spots are covered with a dirty gray exudate, which rapidly changes in color to a dirty yellowish-white, resembling the exudate of diphtheria. Microscopically, it is found to contain but little fibrin and many micro-organisms, especially streptococci. Only in exceptional cases is this coating distinctly membranous in character, as in diphtheria, and then it contains considerable fibrin in addition to the streptococci. Inasmuch as the necrosis mentioned above does not confine itself to the pharynx and tonsils, but may extend to the uvula and soft palate, it is not always possible to exclude a diphtheritic infection. In doubtful cases a bacteriologic examination alone can determine the nature of the infection.
In the favorably progressing cases there is little or no involvement of the nose, and the ulcers heal. The necrosis of the mucous membrane
is apparent only in the anterior faucial pillars. They stand out promi nently and their edges are ragged (Figs. 51 and 52). The tonsils appear to have lost some of their substance; their surfaces are nodular. The temperature falls by lysis unless further complications (car, lymph-nodes) make their appearance.
In the more severe cases the pathologic picture increases in severity. The ulcers on the soft palate extend further into the tissues, and there may be considerable destruction of the soft palate as well as of the uvula. In some cases the necrosis in the tonsils extends to the anterior faucial pillars and may progress to perforation. This may be so extensive as to cause a collapse of the soft palate. A perforation at the base of the uvula may also occur, as the result of extension from the pharyngeal tonsil.
In these cases the process is not limited to the pharynx. Analogous changes are found in the nose and, in the most severe cases, in the larynx.
In those cases where the swelling of the mucous membrane of the pharynx and nose is slight, there is comparatively little interference with inspiration. However, as the changes in the nose become more intense, nasal respiration is impeded and sometimes impossible. The secretion from the nose is profuse, purulent, and malodorous. The skin of the nostrils is irritated. Mouth-breathing alone gives relief; the lips, mouth and tongue are dry, the tongue is leathery and coated, the lips are cracked and there may be necrosis of the buccal mucosa. The accessory sinuses of the nose are similarly involved (antrum of llighmore, sinus frontalis). Because of the disturbed respiration, the patient is restless and sleeps badly.
Involvement of the middle ear is almost a certainty. The inflammatory changes lead rapidly to spontaneous perforation of the tympanum and to an otorrinea, slight in degree, but of considerable duration.
As a rule, the sudden onset of pain in the ear and the pressure tenderness around the ear is sufficient evidence of an impending otitis, but in all cases, even when these warning symptoms are not present, it is advisable to examine the ear with the mirror, because the otitis may otherwise often be overlooked.