(Blastomycetic dermatitis; Saccharomycosis hominis)
Definition – A rare, chronic, infectious, inflammatory disease caused by blastomyces and characterized by well-defined and elevated warty patches, the borders of which are usually studded with minute abscesses.
Symptoms – Most of our knowledge of this rare disease, of which only about sixty cases have been reported, is due to American investigators. The initial lesion appears as a small papulopustule or papule which may remain unnoticed for months, but finally becomes crusted and enlarges peripherally, presenting a sharply outlines, elevated, papillomatous patch. The base of this patch, which may assume some size, is bathed in a seropurulent secretion and presents a sloping, smooth, dark to purplish-red border of an eighth to three-eighths of an inch in width. It is this characteristic border which contains the typical minute deep-seated abscesses. Individual patches take months to attain the diameter of an inch and may remain indolent for months or years afterward, but usually other patches develop during the interim. Healing may be spontaneous or gradual, the center often clearing as the disease spreads at the periphery. Resolution takes place in the form of the gradual disappearance of the papillary projections, the diminution of the serous discharge, decrease in number of the miliary abscesses and the formation of the characteristic soft, supple, pinkish- white cicatrix. The face, hands and arms are most commonly involved, but occasionally the foci of the disease may be some distance apart as in a case of my own which showed lesions on the lower lip, axillae and vulva. Subjective sensations are few and the general health is not disturbed unless systemic infection takes place causing pyemia, subcutaneous abscesses and bone necrosis.
Fig.164 – Blastomycosis, involving the entire vulva and spreading up the abdomen to the navel. Later lesions appeared on the chin and in the axillae. The blastomyces were demonstrated microscopically. Improvement of all lesions and complete disappearance of the smaller ones was caused by X-raying and potassium permanganate (1 : 1000) externally while Arsenicum iod. 3x and later potassium iodid, 5 to 20 drops of saturated solution, three times daily, were used internally.
Etiology and Pathology – Three quarters of the cases of this rare disease are found in men, half of whom are over forty years of age. The sole cause is a local infection by a pathogenic yeast fungus. A slight surface traumatism has been the seat of the invasion in a few cases. The disease is more common in the United States than elsewhere. The microscopic findings are similar to those of warty tuberculosis. The characteristic miliary abscesses are found in all parts of the hyperplastic epithelium. The rete cells are large and swollen, the prickles being conspicuous; premature cornification may occur in groups of cells and the corium is the seat of a variety of inflammatory changes including dense infiltration. The blastomyces may be demonstrated by subjecting a section of the diseased tissue or some of the discharge to a strong solution of potassium hydroxid. They appear as round, oval or irregular bodies having a double- contoured capsule and a granular protoplasm, and may be obtained in pure culture from the minute abscesses so characteristic of the disease.
Diagnosis – Tuberculosis verrucosa has a deeper, usually more dusky violet color and is less extensive. Lupus vulgaris is sluggish in its course, with ulcerative tendencies and tough, firm scars. Sporotrichosis presents indolent abscess formation which is characteristic. The vegetating form of syphilis will present a different onset and course, and respond differently to treatment. Its discharge is more purulent, has a greenish color and an offensive odor. It may be necessary in any case to resort to microscopical examination, experimental animal inoculation or cultures to clearly differentiate the disease.
Prognosis and Treatment – Cases with systemic involvement are usually fatal, but the ordinary type, though obstinate, is not harmful to life. However, recurrences are common and the treatment should be careful and prolonged. Excision and curetting may be indicated, but the most successful treatment consists in the use of the iodids internally, gradually reaching the full dosage, with the necessary interruptions. During the latter some carefully selected tissue salt may be prescribed, plus the local use of weak antiseptic lotions, together with a few exposures to the X-rays. Copper sulphate in 1/4 grain doses internally and the local application of a 1 per cent. solution of the same have been urged by Bevan.