TERIOLOGY) have been shown to be the cause, not only of the common forms of septic impetigo, but of a variety of scaly affections, previously regarded as forms of eczema, which are now included under the heading of Dermo-epidermites microbiennes. Ultra-microscopic organisms, capable of passing through a Berke feld filter, which have become prominent lately in connection with cancer (see CANCER; FILTER-PASSING VIRUSES), would seem to be responsible for the small epidermal growths, known as Mollus cum contagiosum, and it is more than probable that similar or ganisms will be found to be the cause of other types of benign and malignant epithelial growths. In the Tropics, the so-called Calabar swellings have been found to be of filarial origin, and the Oriental sore to be due to a parasite of the trypanosome family.
Focal infection, in the sense of protein poisoning from bacteria in some crypt or tissue, or in the ali mentary tract, has of late years been advanced as a possible cause of Lupus erythematosus, circumscribed patches of eczema, and other erythematous conditions, and the improvement in them which sometimes follows the injection of an autogenous vaccine has been taken as evidence of an etiological connection.
Although certain affections of the skin, such as Herpes zoster, or shingles, have been proved to be of nervous origin, the trend of recent research has gone to show that the influence of the nervous system as a cause of cutaneous disease has been overrated, and that a number of affections, which were vaguely attributed to reflex nervous disturbances, are either of toxic origin, or due to imperfect action of a ductless gland, or to some disordered state of the blood.
The doctrine of anaphylaxis (q.v.) has con tributed to our knowledge of certain cutaneous phenomena, and has explained the liability to recur of a dermatitis due to local irritation, or to the presence in the blood of some foreign protein.
Recent advances in treatment have been re markable. Internal treatment has become based more on general medical principles and on the discovery and correction of some underlying disturbance in an organ or system than on so-called specific medication. That sheet-anchor of the earlier physicians arsenic—has lost its position as a panacea for chronic skin affec tions, and any value it may have in the treatment of psoriasis, pemphigus, etc. is being regarded more as the result of its value
as a nerve tonic than as a specific drug. It has attained, however, a new importance in its organic preparations, in the treatment of syphilis (see VENEREAL DISEASE).
The increase in our knowledge of the duct less glands (see ENDOCRINOLOGY) has added organo-therapy to our methods of treatment, and thyroid medication has proved to be of benefit in various skin affections in childhood, associated with retarded development, and especially in mild ichthyosis, in which eczematous changes are so liable to be superimposed.
The value of vaccines (see VACCINE THERAPY) in the treatment of skin diseases has been overrated, and their use in the past was too promiscuous. They are of most value in acute suppurating lesions of staphylococcic origin, such as recent boils. The development in local treatment has been even more striking than that from internal medication.
with carbon dioxide as the freezing agent, is a useful means of destroying vascular naevi, moles, warts, superficial rodent ulcers, and of ameliorating Lupus erythematosus of the fixed type. Diathermy has proved of great value in inoperable cases of rodent ulcer, and for cauterisation of malignant growths in the mouth or naso pharynx (see ELECTRO-THERAPY).
Rachotherapy.—The greatest advances in late years, how ever, have taken place in connection with radiotherapeutics (see RADIO THERAPY) . The newer methods of X-ray dosage, made possible by the use of the Coolidge tube, have increased the useful ness of the X-rays as a means of healing chronic ulcers, relieving local irritations, reducing epidermal thickening and causing the defluvium of the hair for the cure of ringworm of the scalp. Radium has proved to be of special service in the treatment of rodent ulcers and hypertrophic scars (see RADIUM THERAPY). The value of the actinic rays of light, when applied locally, in the treatment of tuberculosis of the skin, and in healing chronic ul cers, has been greatly enhanced by its use over the whole cutane ous surface, in the form of actinic ray baths, which have been found to improve the general health by stimulating metabolism and increasing the bactericidal power of the blood. See HELIO THERAPY.