(Chromophytosis; Pityriasis versicolor; Mycosis microsporina; Dematomycosis furfuracea)
Definition. A vegetable parasitic affection, due to the microsporon furfur and characterized by irregular, variously sized, yellowish-brown macules, usually situated upon the trunk.
Symptoms. The early manifestations are pin-head-to pea-sized, round, pale- yellow to brown, irregularly scattered macules. The scaling, which is fine, can be made apparent by rubbing the affected surface. Many of the lesions slowly enlarge and together with new spots form by coalescence irregular, map-like patches often of large dimensions. They may have sharply defined edged, barely elevated above the surface of the skin and occasionally assume an annular form. The skin is commonly dry unless sweating is active and generally presents little itching unless the patient becomes heated. Tinea versicolor is usually located on the trunk, especially on the anterior chest wall, but is not uncommon on the back and abdomen, even extending at times to the arms, neck, groins, thighs and buttocks. Commonly the invasion is slow and, untreated, the conditions may last indenfinitely. It usually disappears or becomes less vigorous in the cold months and reappears in the warm season. Curiously enough, in the colored race, the fungus may produce gray or white patches on the skin.
Etiology and Pathology. Male adults are more often affected. It is rare in childhood and in old age. It would seem that a certain condition of the skin must preexist favoring the growth of the fungus because the disease is so feebly contagious that it is not readily communicated from one person to another. Free sweating appears to be a factor for it is more common among those who exercise especially athletes. It is said to be relatively frequent in consumptives but I have never been able to verify this assertion. While it may occur in any climate, it is most frequent in warmer latitudes. The disease is due to the microsporon furfur discovered by Eichstedt in 1846 and later named by Robin. It is located in the corneous layer of the epidermis, where the causal element, a vegetable mold, may be found. For microscopical examination scales are scraped from a lesion washed in ether to remove the fat, moistened with dilute liquor potassae and flattened out on the glass slide. Both spores and threads are more readily stained with eosin and methyl-violet than those of ringworm or favus. Under the microscope the spores are found to be larger than those of ringworm, rather uniform in size, and more or less grouped in grape-like bunches. Mycelia are numerous, rather short and usually unbranched.
Diagnosis. Chloasma occurs chiefly on the face, is not scaly, cannot be removed by scraping, and contains no fungus. Erythrasma occurs on the moist regions of the skin, in darker patches, and its organisms are much smaller. Dermatitis seborrhoica is not usually confined to the trunk, seldom merges into large patches, and its scales are fatty and large with no evident of candidia and mycelia. Pityriasis rosea eruption is not limited to the trunk, has silvery scales and the patches appear slightly yellowish only as it fades away. The macular syphilid occurs in discrete, non-scaly round spots which will be found upon the face and legs, as well as on the trunk, and usually in association with other signs of syphilis. The vitiligo lesion is round and the contiguous pigmented border is concave without sacliness, while the discoloration of tinea versicolor is convex with marked scaliness.
Prognosis and Treatment. This disease is benign and readily curable if properly treated. However relapses are common, owing to failure to thoroughly destroy the fungus.
Mechanical removal of the outer layer by friction with pumice stone, hot water and soft soap, followed by the persistent application of a parasiticide, should readily cure this disease. I prefer an aqueous saturated of coarse toweling once or twice daily for a period of one to two weeks. Even though the disease appears to have fled, treatment should be renewed occasionally and a strict watch kept of local conditions. If the surface involved is not large, the patch may be painted with tincture of iodin, but when the eruption is extensive, a bath containing 3 to 4 ounces of liquor calcis sulphurata (Vleminckx’s solution) to 30 or more gallons of water, will be found useful. In all cases, underclothing, towels, etc., should be backed, boiled or destroyed to prevent reinfection. Internal medication may be necessary for the relief of associated symptoms, but never for the fungus growth. See Kali carb., Kali sulph., Nat. arsen., and Sulph.