Between sixty and seventy drugs are known to produce distinct forms of dermatitis, such as copaiba, cubebs, the various preparations of iodine, bromine, and arsenic, some of the aniline preparations, quinine, etc.; while the various antitoxic serums, especially that of diphtheria, will sometimes produce a skin disturbance. In these cases it is only necessary to recognize the source of the trouble and remove the cause by stopping the drug. Should dermatitis produce such restlessness as to interfere with the physiological rest necessary for a wound or fracture an opiate should be administered.
DERMATITIS CALORICA.
Dermatitis calorica means the varying degrees of irritation which may be set up by extremes of heat and cold, continuous or alternate, as in so-called chilblains. These are often seen upon the feet, but occur upon the hands and even the face, i. e., in places most exposed and least supplied with blood. The lesion occurs in patches, often with livid discoloration, and causes sensations varying from discomfort to acute pain, almost always aggravated by warmth; while the skin appears inflamed, though to the touch it usually seems cool.
Treatment.
—Chilblains occur most frequently in the anemic and those with uric-acid diathesis, but may be met at any time. The constitutional treatment should not be overlooked. Much pertains to good care of the feet, especially after exposure. After wetting or chilling they should be dried and then rubbed with boric-acid talcum powder, containing 1 or 2 per cent. of menthol; this may be dusted upon the feet, before going outdoors, upon return, and when there is discomfort.
It will often give relief to immerse the feet in warm water containing sufficient tincture of iodine to give it a mahogany color; or the feet may be simply dipped in this and then allowed to dry without using a towel. The use of hydrogen dioxide diluted two or three times has been highly commended. If this proportion of dioxide be added to four or five parts of hot saturated solution of sodium bicarbonate the efficacy of the measure will be much enhanced. In extreme cases frequent use of the following formula will probably give more relief than anything else: Carbolic acid 1 part, ichthyol and tincture calendula each 4 parts, and glycerin 16 parts. With this the skin may be kept constantly moistened.
The expressions of dermatitis produced by heat may vary from an efflorescent rash to complete destruction, and will be treated of under the following head:
BURNS AND SCALDS.
The term “burn” is applied to lesions produced by flame or dry heat, while moist heat (i. e., boiling materials or steam) causes injuries known as “scalds.” Between the two there is but little essential difference, except that with the latter there is usually loosening of the hair of the part, and sometimes much loosening of the epidermis as well, so that it is easily detached in more or less large patches. Whether heat is relatively feeble but prolonged, or higher in degree and of shorter duration, the results of dry heat are about the same. Some differences will exist according to whether the part is exposed to actual flame or to hot or melted material, sufficiently hot perhaps to cause complete charring or carbonization of a part.
Fig. 97