Definition:—An acute infectious febrile disease of childhood, characterized by a peculiar eruption. It very seldom attacks individuals above the age of puberty, and is most common before the age of ten years.

Etiology:—The exact cause is not determined, no microorganism having been isolated. It occurs in an endemic or epidemic form, is readily conveyed by direct contact, by fomites, by food, and through the atmosphere. One attack usually renders the patient immune to subsequent infection.

The disease, from the appearance of the eruption, may be mistaken for a mild case of smallpox. And there is some difficulty in some severe cases, in making a differential diagnosis. There is no relationship whatever between the two diseases, and one does not protect from an attack of the other.

Symptomatology:—The period of incubation lasts from seven to fourteen days. In young children and in infants there is restlessness, fretfulness, wakefulness with a disordered stomach. In other children there is backache, malaise and general indisposition. Fever occurs usually without marked chill, or with chilliness too slight to attract attention, as the first marked symptom. This at first is moderate, but will ultimately rise to 103° or 104° F. In many cases, while the child is not well, the fever does not attract attention until the eruption appears. Small papules at first appear on the forehead or face. These rapidly increase on the face, neck, shoulders, back and chest. Those first appearing quickly become vesicles containing serum. Each one is isolated and the skin at the base is unchanged in color and in appearance. The eruption is discrete, never confluent and never very profuse, and it seldom appears upon the mucous membranes. While the shape and casual appearance of the vesicle will suggest that of smallpox, at first, the distinguishing points are sufficiently marked. It is flattened when matured, but not umbilicated, there is no induration at the base and it is superficial. Later, however, the vesicle becomes a true pock, containing an opaque serum. Upon scratching the pock may become infected and contain pus. The pocks contract and shrivel by the fourth day, crusts form and fall off, and the larger ones leave a scar closely resembling that of the smallpox scar.

The vesicles which form first, pass through all the stages to maturity and disappear while others are continually forming, so that by the third day the eruption is present in all the stages of its development.

Diagnosis:—Many cases of chickenpox appear when the child is thoroughly and effectually vaccinated. This excludes smallpox, which is the only disease it is mistaken for. The mildness of all the symptoms, especially those premonitory of the disease, are widely contrasted with those of smallpox.

The vesicles dry up quickly, are seldom umbilicated and have a dark scab. They are superficial and the base is not indurated. Chickenpox runs a short course, and terminates abruptly, in the usual health.

The disease is not a severe one or one attended with serious results. In ordinary cases the child may be confined to its bed, but may continue to play with its playthings. In frequent cases it will pass through the entire course of the disease without going to bed during the day. If the patient be reduced by some previous illness, the severity of this disease is increased. In an occasional epidemic every case will be severe, but usually without sequelae. If the vitality is seriously impaired or if there be general infection or local infection of the skin, septicemia, or pyemia, with sloughing and gangrene, may result. Erysipelas, glandular enlargement and nephritis are the most common sequelae.

Prognosis:—The mild character of the disease renders the prognosis always favorable.

Treatment:—In many cases the physician is not consulted. Usually the tongue is coated, moist and pasty, and the mucous membranes of the mouth are pale. An alkaline remedy, as sodium sulphite, the neutralizing cordial or the plain bicarbonate of soda in two or three full doses in water should usually introduce the treatment. Aconite in minute doses for fever will be all sufficient, unless nervous excitement be present, when a nerve sedative should be added. The kidneys should be watched and their normal action sustained.

Any complications may be met, as they appear, with the indicated remedy. They are unusual.

The Eclectic Practice of Medicine with especial reference to the Treatment of Disease, 1910, was written by Finley Ellingwood, M.D.