Some discolorations of the skin are due to the introduction of coloring substances from without or from other organs, thus the bile in icterus (jaundice) can color the skin almost any shade of yellow. Arsenic is well known, after excessive or prolonged dosage, for its diffuse, brownish pigmentation, and toxic gases, picric acid, chrysarobin and other preparations cause temporary staining.
Argyria is a form of a discoloration from the prolonged administration of silver salt internally, especially silver nitrate, or in workers in silver from the penetration of the epidermis by minute particles of the metal. A similar condition to the latter has been noted in workers in antimony, lead and other metals, as is shown by the accompanying illustration. The typical color of argyria is a bluish-gray or slate. While the deposits may not affect the general health a change of occupation will always benefit. Potassium iodid and mercurial vapor-baths have given more or less satisfaction in the treatment.
Tattoo marks represent permanent discolorations of the corium caused by the mechanical introduction of carbon, cinnabar, carmin or indigo. The process is known as tattooing and it is needless to describe the artful and fanciful decorations which ensue. They only interest the dermatologist because of his efforts to remove them. Electrolysis may succeed with the smaller spots but the cutaneous trephine is the most reliable agent.
Fig. 97. – So-called trade eruption, due to many years’ handling of antimony and lead. Similar to argyria in appearance and history. The lesions are deep- seated, brownish-black, non-inflammatory macules.
Excision, if scarring is no objection, can be used although secondary skin grafting may be necessary. Powder marks or stains are of like appearance and nature and when superficial, solidified carbon dioxide will remove them as it will superficial tattooing. In recent years varying success has been reported in the removal of both these conditions by tattooing in, after first rendering the surface aseptic, the glycerol of papoid. Caroid has been used as a solvent in the same manner.
FIG. 98. – Cutaneous punch or trephine (three – fourths actual size.).