Fig. 243.—Sebaceous eczema, second stage. Partial alopecia.
Fig. 244.—Sebaceous eczema, third stage. Total alopecia.
The hairs, however, when examined microscopically are found to be thickened at their roots, though otherwise throughout their whole length they remain normal. The condition is a consequence of disturbance in the circulation and nutrition of the papilla and the root of the hair.
Finally, the congestive process extends to the sebaceous glands, the secretion of which it modifies, and sets up seborrhœa, which is responsible for the formation of the crusts and epidermic scales above-mentioned.
The pathogeny of the disease is difficult to explain, but the stages in the clinical development are as follows: the skin undergoes repeated attacks of congestion, followed by seborrhœic folliculitis, epidermitis and loss of hair.
The diagnosis is easy, the absence of ringworm being proved by the absence of the spores of trichophyton and by the non-contagious character of the discharge.
The prognosis is not grave from the point of view of general health, the chief functions being perfectly regular, but it is otherwise as regards possible terminations, viz., partial or total loss of the coat, which may be irremediable.
Treatment. It is difficult to lay down a really satisfactory method of treatment, because the exact cause of seborrhœa is still unknown. As it is probably to be sought in some individual constitutional peculiarity, the feeding and method of life should be changed and the skin stimulated by washing with lukewarm water and soap and by dry friction. Locally, if the alopecia threatens to be permanent stimulating applications may be tried. These comprise lotions containing alcohol, solutions of chloral, salicylate of soda, etc., and they should be applied with smart friction.
The sufferers should not be used for breeding purposes.