A number of diseases are apparently favorably affected by light.
The common cold, both as to prevention and treatment, is still in the doubtful class. There is evidence from some workers who make claims for the use of ultraviolet radiation, that it prevents frequent colds. They advise brief exposures a few times weekly of the entire body. However, the most careful observers are still unwilling to believe that this has any positive effect.
The use of light as a general tonic is also probably overdone today. Sun lamps and ultraviolet lamps have become somewhat faddish methods of treatment and are used in a great variety of diseases. For instance, in the convalescent period of grippe, influenza, pneumonia, typhoid fever, rheumatism, arthritis, asthma, etc. There is little evidence that light treatment does much good in these miscellaneous conditions. At the same time, it does no harm unless there is an over-dosage which causes inflammation of the eyes or burns of the skin.
The only possibility that it could do any good in these conditions is that sunlight seems to have an effect upon the blood. It undoubtedly does help secondary anemias, causing a regeneration of iron and new formation of red blood cells.
Therefore, it is of possible value in all forms of anemia, and as anemia is present after any severe illness, this may be the secret of the good results claimed for its use in convalescence from such diseases.
In skin diseases it has considerable usefulness. In acne or pimples, ultraviolet light assists materially in cleaning up the infection. Also in boils, carbuncles, and skin infections, generally. Superficial skin ulcers tend to heal under its influence. Tuberculosis of the skin has been treated by light since the days of Finsen.
Chilblains, or frost bites, are also benefited by exposure to ultra-violet light. The painful redness, swelling and itching are greatly alleviated.
It appears that ultraviolet light is of aid in skin grafting cases, the number of takes being increased when the area is exposed to ultra-violet light or sunlight.
The many claims for the light in falling hair and baldness have, according to Dr. Edgar Mayer in his book, “The Curative Value of Light,” published by D. Appleton and` Company, not been substantiated.