CHAPTER XXXII

TINEA CRURIS

GENERAL CONSIDERATIONS

Under the name “dhobie itch” this fungus affection is probably better known to Europeans than any other tropical skin disease. This name dhobie or washerman’s itch has been given on account of associating it with the infection of the underclothing while being washed in the pools or streams along with the garments of those who have this skin disease. This, like every other widespread view, has probably some foundation but cannot be verified. It is the eczema marginatum of Hebra.

This affection is caused by various species of _Epidermophyton_. This genus differs from _Trichophyton_ in that it never invades the hair or hair follicles.

The species which have been more frequently reported are _Epidermophyton cruris_, _E. perneti_ and _E. rubrum_. The mycelium is about 4 microns broad and the spores about 5 or 6 microns. All of these fungi can be cultured on Sabouraud’s maltose agar, growth appearing in about a week, except _E. perneti_, which grows more rapidly.

SYMPTOMATOLOGY

The favorite site is the crotch although the axillary region is also frequently involved. The process starts as a papule but these rapidly develop and give rise to an angry red, swollen patch with sharply delimited margins. These red, festooned patches are usually limited to the perineum, scrotum and inner surfaces of the thighs.

The itching is unbearable and many secondary infections or eczematous lesions result from the fierce scratching of the parts.

If the patient goes to a cooler place the process subsides to return when he comes back to the hot moist climate where the infection was originally contracted.

In some cases the fungus invades the region between the toes and gives rise to intolerable itching and from secondary bacterial infections to a condition known as “Mango toe.”

It has seemed to me that when one has a coccal infection engrafted upon the fungus one the condition becomes what might be termed fulminating, so rapidly does the itch extend.

TREATMENT

When the process is markedly inflammatory mild applications are indicated, such as calamine lotion (30 grains each of calamine and zinc oxide with 5 or 10 drops of carbolic acid in 1 ounce of saturated solution of boric acid).

A 10% to 15% solution of sodium hyposulphite can, however, be used on the area even when markedly inflammatory.

Iodine applications are too irritating for the region of the scrotum.

An ointment of resorcin, 20 to 30 grains with 1 dram of sulphur to the ounce, may be tried. If chrysarobin be used it should be applied with greatest care as noted under tinea imbricata. Many advocate applications of solutions of salicylic acid in alcohol, 2% to 5%.

Manson’s dusting powder of equal parts of boric acid, zinc oxide and starch should be freely used.

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