Fox-Fordyce Disease

FOX-FORDYCE DISEASE (morbus Fox-Fordyce, prurigo chronica circumscripta axillaris et pubis), a peculiar skin disease, first described in 1902 by Fox and Fordyce and characterized by extremely sharp itching and the appearance of nodular elements in the area of the axillary fossae, sometimes in the area of the pubis, navel, perineum, genitals, and mammary nipples. The nodular elements, the size of a pinhead, the color of normal or slightly reddened skin, with rounded outlines and a matte-shiny surface, are located in the orifices of the follicles, having in the central part an accumulation of horny scales in the form of a plug closing the opening of the follicle. The hair in the affected area appears dry, dull, and broken. The surrounding skin is often lichenified. The etiology and pathogenesis of the disease remain unclear. The disease is considered a special form of neurodermatitis in areas of the skin supplied with apocrine glands. Against such an interpretation, the following considerations are cited: in neurodermatitis, nodular elements quickly transition into phenomena of lichenification, and neurodermatitis easily yields to X-ray therapy, which is completely uncharacteristic of Fox-Fordyce disease. Others believe that the nodules primarily forming in the orifices of the apocrine glands cause obstruction of the glands, and the retained secretion of the glands causes toxic phenomena, accompanied by sharp itching, which in turn contributes to even greater obstruction through the formation of hyperkeratotic layers in the orifices of the apocrine glands. Some authors are inclined to link the disease with dysfunction of the sex glands, others with dysfunction of the adrenal glands, etc. In general, the disease likely represents a special form of dermatosis, closely related to neurodermatitis. Symptomatology boils down to sharp, sometimes intolerable, itching appearing in violent bursts in the area of skin involvement and the formation of characteristic nodules in the orifices of the follicles of the apocrine glands. The lesion is noted almost exclusively in women, with 3/4 of all cases involving the axillary fossae, followed by the pubic area, the area of the navel, mammary nipples, groins, perineum, and genitals. Pathological anatomy boils down to phenomena of hyper- and parakeratosis and acanthosis on the part of the epidermis, mainly in the orifices of the apocrine glands. The ducts of the glands and the glands themselves are dilated; the ducts are filled with keratotic plugs, as are the hair follicles. In the papillae and the subpapillary layer, there is perivascular infiltration, especially noticeable in the vicinity of the glands and hair follicles, consisting mainly of round-cell elements (occasionally mast and plasma cells). Diagnosis is easy based on the characteristic localization, nodular elements, and itching. Differential diagnosis with acanthosis nigricans is easily conducted based on the essential signs of one or the other disease. Treatment consists of the use of various antipruritic agents. In some cases, a good effect is obtained from the use of X-rays, and it should be borne in mind that the usual doses of rays, such as those used for the treatment of chronic eczema and neurodermatitis, often prove ineffective, which is why some recommend harder rays (with zinc and aluminum filters) to act on the apocrine glands in the sense of suppressing their activity. In exceptionally persistent and distressing cases, some recommend excision with subsequent skin transplantation.