Chickenpox, or varicella, which is a most highly communicable disease, is one of the two examples in which the rash appears in successive crops— the other example being typhoid fever.

Infection is direct or indirect, and the disease is infectious from the commencement of the illness, before the rash appears, until the last scab separates. The incubation period is from 10 to 25 days, with an average of 14—18 days. Infection may also follow contact with a case of herpes zoster.

Symptoms. The onset may be so slight as to pass unnoticed, and the rash, as it appears after 24 hours, is often the first sign observed. The rash of chickenpox is vesicular, each vesicle containing inflammatory exudate, and when the vesicles first appear they are bright and shining, but after a few hours lose this shimmering effect and become dull. The rash appears first on the body, inside the mouth and on the scalp. In a day or two some lesions of the rash will be seen to have become slightly purulent, others have dried and scaled off; the purulent ones will form scabs, which will separate later. As the rash spreads, most of the body will be covered, and it is also seen on the face.

Crops of the rash appear daily for several days, so that it is quite usual to see clear vesicles, vesicles filled with purulent fluid, dried vesicles scaling off and scabs—all on the same area of skin.

The temperature may be raised a little, but this depends on the density of the rash and the amount of pus present. The rash is irritating and the patient is inclined to rub and scratch the irritable area, and this causes the scabs to be knocked off, delays healing and may result in scarring.

Treatment. The patient is kept in bed for the first week or two, and ordinary nursing measures will be necessary; in addition the precaution of having non-irritating clothing next to the skin should he taken. When the rash is very irritable bathing with weak carbolic lotion, or dusting with an astringent powder and applying an ointment containing a mild antiseptic may give relief.

Complications are rare; in debilitated children gangrenous pocks may develop, and impetigo may arise as a secondary infection.

[Chickenpox]  [Vaccination]