Acne Rosacea is a term which includes so-called seborrhoeic dermatitis of the face, but especially recurrent and the stereotyped hyperaemia of the face caused by constant external producers of local blood congestion such as sun, wind, fire, heat, etc., and frequently reflex from gastro-intestinal, and in the female, genital disorders. In the gastro-intestinal cases a careful dieting, and exclusion of large quantities of badly made tea, and excess of alcohol is most essential.

We now come to Class II of cutaneous reactions in which the nervous system is prominently involved. The reaction may occur in course of a defined nerve lesion, as syringomyelia, hysteria, and dermatophobia; or as secondary to internal secretory troubles, as exophthalmic goitre and myxoedema and Addison's disease; or as trophoneurotic syndromata illustrated by such conditions as Raynaud's symptoms, erythromelalgia, erythromelie, scleroderma, nerve panaris, hemiatrophia facialis, ainhum, perforating ulcer, recurrent phylctenosis of the extremities, epidermolysis, alopecias, and secretory troubles of the sweat and sebaceous glands; or as the pigmentary disturbance known as vitiligo or leucoderma. None of these troubles seem to be directly affected by diet, and, as a rule, only a rational diet is called for. I have often seen leucoderma in spare, delicate-looking children, which suggested the importance of a specially nutritious diet to avert tuberculosis. In the sweat secretory troubles it is advisable to avoid stimulating food, and excess of fluid, which are apt to increase the trouble. Opinions differ as to the cause of acne vulgaris. It is a reaction of the period of evolution of puberty, and is associated with excessive output of sebum, plugging of the sebaceous follicles, and secondary papulo-pustular complications from the growth of staphylococci. The plugs consist of a proliferation of epidermic cells in the mouths of the follicles enclosing, and caused by, myriads of micro-bacilli. Whether these bacilli, which certainly cause the plugging of the mouth of the follicle, are the cause of the seborrhoea and consecutive changes, or whether the seborrhoea is a functional disorder of puberty affording a congenial soil for the bacilli is in dispute. These acne patients are often debilitated generally, and frequently are dyspeptic and constipated, so that a simple bland and laxative diet is called for. Some French dermatologists cut off all fatty food.

Class III comprises the cutaneous reactions characterized by nutrition troubles, and includes (A) changes characterized by exaggeration of nutrition, (a) of the epithelium as in keratosis pilaris, lichen spinulosus, keratosis follicularis vegetans, acanthosis nigricans, porokeratosis, and keratosis palmaris et plantaris; (b) of pigment, (c) of hairs, (d) of the dermis, as in dermatolysis and soft naevi; (e) of subcutaneous cellular tissue as in many naevi; (B) changes characterized by diminution of nutrition, as in albinism, canities, alopecia, tricho-rexis nodosa, monilithrix, primary nail and cutaneous atrophy; and (C) mixed acquired dystrophies of the hair and nails; of epidermis and dermis, as in ichthyosis, xeroderma pigmentosum and colloid milium; of the elastic tissue, as in pseudo-xanthoma elastica. There are not any special diet indications in this class.

Lastly, there is Class IV of cutaneous neoplasms which need not be discussed.