THE DERMATOLOGIST LOOKS AT THE HAIR PROBLEM 131 morning he found that his dark brown hair had turned white with the exception of a few strands and within the next few days, there occurred a considerable loss of frontal, marginal, and facial hair. While extreme examples of this type are rare, less pronounced cases are undoubtedly not too in- frequent. The question of graying of hair will be referred to again. The endocrines appear to be in- volved in hair growth in some man- ner. The glands which seem most important are the suprarenals, gon- ads, thyroid, and the pitui-tary. The latter two may not have any real direct effect, but may react on the suprarenals which in turn in- fluence the hair. The thyroid is said to particularly affect the hair of the scalp, eyebrows, and eye- lashes. The ovary and testes in- fluence the development of pubic and axillary hair, the testes, the body hair and beard. The hypoph- ysis and suprarenal through in- fluence on the testes indirectly in- fluence hair generally except the capillus, eyebrows, and eyelashes. According to Hamilton (4) common baldness (alopecia) is a sequela of sexual maturation and is, in most instances, induced by stimulation from male hormone substances. In keeping with this physiological re- lationship, the incidence of the disease is much higher in males than in females, and extensive forms of the disease are restricted almost entirely to males. Most women with pronounced forms of the disease are those with virilism. Apparently, age is a factor in the rapidity with which areas of de- nudation extend. In eunuchs, sus- ceptibility to such loss of hair can increase with age, but baldness does not occur because of inadequacy of testicular secretions. This increased susceptibility accumulates, unspent, like money in the bank, and later treatment of the eunuchs with an- drogens results in a rapid loss of hair. Available evidence does not bear crucially on the question of whel•her or not there is, with in- creasing age, a lowering of the amount of androgenic stimulation required to produce baldness. The third factor known to be in- volved is inheritance. No amount of androgenic stimulation produces baldness in persons who lack an in- herited tendency to this disease. The realization of this tendency de- pends, however, upon androgenic stimulation, since, whatever the inheritance, baldness does not ensue without androgenic stimulation. Local areas of the skin play a dominant role in the atrophic changes that result in baldness. Application of androgens directly to a local area results in piliary changes limited to that region. At the present stage of our informa- tion, it must be assumed that andro- gens are only one of what might be a family of agents (although they are the usual one) which may be cap- able of inducing atrophic changes in s•ecific areas. The degree of atrophy is controlled by the local area of skin and does not result from external changes in vascularity

132 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS or compression of the area by tight bands. Rather, baldness will occur even in skin transplanted from its usual site. Baldness is one of the so-called degenerative diseases which remain as extremely important medical problems and have not benefited from the achievements of chemo- therapeutic control of infectious diseases. It is a condition, the progress of which can be studied. The nature and therapeutic control of the disease can be investigated carefully. Findings fr6m studies of this disease may be presumed to be applicable to a number of so-called degenerative diseases, like prostatic cancer. Vitamin deficiencies in experi- mental animals certainly play an important role but whether vita- mins are of equal importance in humans is not yet so clearly estab- lished. This will be discussed in de- tail under graying of the hair. From the standpoint of local measures even the effect of shaving or cutting of hair on rate of re- growth has not been satisfactorily settled. While it is believed that shaving or cutting has no effect on the rate of regrowth and does not stimulate the fine downy hairs into becoming terminal hairs, the work is not entirely conclusive and should be repeated. The reverse of this picture is the question of whether the destruction of one hair by.elec- trolysis does not possibly stimulate other hairs of this particular hair group and as a result increase the growth of the other hairs or stimu- late follicles in a resting condition. There is competent work to show that this is the case but the majority of physicians believe that destroying one hair by electrolysis has no effect on the rate of growth of other hairs in the same group in the same patient. Again the point is not settled. The Effect of Temperature. Heat and cold are both said to influence the rate of hair growth but the effect is probably slight and brought about through the nervous system or through variations in vascularity. There are races of rabbits which tend to produce light or dark hair de- pending on the temperature in which they are kept. Radiation effects have been stud- ied and it is thought that the actinic rays--ultra violet--exert only a slight favorable action on the growth of hair but it is felt that this might be due to the hyperemia that may be produced rather than to any effect of the rays themselves. Again the matter is not settled. The x-rays alone are definitely known to stimulate hair regrowth. Large doses of x-rays or radium of course may cause either temporary or permanent hair loss but less ex- cessive doses because of their depth effect are known to stimulate hair regrowth. This can be beautifully demonstrated in cases of alopecia areata where the exposure of a small sharply demarcated portion of a large bald patch.m the x-ray results in hair regrowth in this area while the rest of the patch remains bald. With all the hair tonics, hair ex-