Seborrhoea Sicca

In this variety there is excessive formation of sebum, possessing more nearly the character of the normal secretion, that is, less fluid than in the last named affection. There is also a larger proportion of epidermic cells, and these, mingled with the oil, dry upon the skin as thin, slightly adhering, and usually circumscribed crusts. The affection is usually of an extremely mild inflammatory type, with slight redness of the skin underlying the scales. It may be found on the situations favored by the last mentioned variety, or upon the chest in man and other parts where the sebaceous glands are well developed, but the hairs not so abundant or long as upon the head, except in infancy, during the early periods of which it is quite common.