In a discussion of the dietetic treatment of diseases of the integumentary system we are faced with the uncertainty or complicated etiology of many of them. To enable the reader to attack the problems under discussion with the knowledge that we at present possess, it will be convenient to survey the morbid processes according to the etiological classification arranged by Louis Brocq of the Hopital St. Louis in Paris. It will be apparent that in a large number of cases the diet, though not without importance, is a secondary or minor factor in the treatment, yet it has to be adjusted in relation to the different stages of the malady or complicating lesions of important organs. But there are affections, such as pellagra and some forms of urticaria, directly associated with a diet which is noxious to the patient, and it is very necessary to realize that in many skin eruptions the predisposition or vulnerability of the soil is an all important factor, and may be contributed to by improper diet or imperfect metabolism of foods. Then again the excessive use of alcohol notoriously helps to render eruptions aggressive and intractable, and in some people leads to the excessive formation of fat, diffuse or in peculiar tumours, and such persons are liable to acquire a vulnerability of the skin leading to rupture of the elastic tissue and the condition known as linear atrophy.
I propose in this chapter to indicate chiefly the general principles on which dieting in the various skin diseases should be arranged, for the details of diets proper for gouty, obese, diabetic and other subjects will appear elsewhere in the book.
The important thing is to grasp the principles on which special diets are indicated, and then the observer can fill in the details, for as will be seen some cases differ greatly in the complexity of their etiology.
Group I, entitled the true morbid entities, includes the class of artificial dermatoses due to external causes such as traumatisms, mechanical, physical, chemical; irritating secretions as in intertrigo and the dermatitis genitalium from diabetic urine; artefact lesions; and the huge group of occupation dermatoses. It is important to realize the fact that damage and reaction may vary with the vulnerability of the soil, and a well regulated bland diet is desirable in the treatment, and to prevent recurrences, for some irritants are only effective when acting on a vulnerable soil. It is our daily experience to see a washerwoman or scrubber go unscathed for years, and then her health deteriorates from some cause, and the irritants encountered in her occupation excite a dermatitis. We shall have something more to say on this point when we speak of eczema. In chilblains we see the vulnerable soil due to a weak circulation, which is often associated with poor nutrition, and the excitant in the onset of cold weather. It is evident that the general nutrition should be fostered by generous feeding, including much fatty diet.