In gangrenous varicella the vesicles, instead of drying up in the ordi nary way, become black and get larger, so that a number of rounded black scabs, with a diameter of half an inch to an inch, are scattered over the surface of the body. If a scab be removed it is seen to cover a deep ulcer. Around it the skin is of a dusky red color. All the vesicles do not take on the gangrenous action, so that we find many varicellous scabs of ordinary appearance mixed up with the blackened crusts. The gangrenous process often penetrated deeply through the skin to the muscles, but under some of the scabs the ulceration is more shallow. These cases are very fatal. Mr. Warrington Haward has reported the case of a weakly baby of twelve months old, who weighed only six pounds and a half. This child was at tacked with gangrenous varicella and died in a few days of pyaomia with secondary abscesses in the lungs.
Diagnosis.—It is often a very difficult matter to distinguish between chicken-pox and modified small-pox. If the eruption follows very rapidly upon the first signs of fever, the disease is probably varicella, for in the case of varioloid the rash is usually preceded by two or three days of fever and malaise with vomiting ; and the pain in the back may be as intense as in the unmodified form of the disease. But there are many exceptions to this rule, for in some cases of varioloid the normal duration of the pre eruptive period is considerably shortened. Again, the spots in varioloid, as in variola, are grouped in threes and fives, while in varicella their distri bution is more irregular. Then, the papule in varioloid is always spotty and hard. In varicella it is peculiarly soft, and always disappears on. stretching the skin. If there be an elevation left after the fall of the scab, it is conclusive in favour of modified small-pox ; while a subnormal tem perature occurring as early as the tenth clay would point rather to varicella than to varioloid. According to Mr. Macuna, the varicellous vesicle is uni
locular, and can be emptied by one touch of a needle. The vesicle in small-pox, on the contrary, is always multilocular, and cannot be emptied by a single puncture. In case of doubt this difference will serve as a dis tinguishing mark.
It is important to be aware that a shallow pit or scar may be left here. and there upon the skin after undoubted varicella. Pitting may occur in any case where, from the irritation of continued scratching, or from some constitutional peculiarity of the patient, ulceration of the skin ha8 been set up in the site of a vesicle.
Gangrenous varicella is distinguished by the history of the case, and the appearance of ordinary varicellous scabs mixed up with the blackened and gangrenous crusts.
Treatment.—A child attacked by chicken-pox must be removed from other children, and prevented, if possible, from picking or scratching the spots. If there be much fever, he should be confined to bed and his bowels must be attended to. When the disease is at an end, the child will require a tonic, such as quinine or iron. If convenient, he may be taken to the sea-side ; and if there be any consumptive tendency in the family change of air during convalescence is not unimportant.
In cases of gangrenous varicella little can be done beyond supporting the strength with good food suitable to the age and degree of feebleness of the patient, and giving the brandy-and-egg mixture as often as is required. If the gangrenous crusts are few in number, the scabs may be removed and the underlying ulcer filled with iocloform powder, as recommended by Parrot for gangrene of the vulva.