Fox-Fordyce disease (FFD), also known as apocrine miliaria, is a rare and chronic pruritic condition that involves severe itching of the skin, predominantly in areas where apocrine glands (fatty sweat glands) are located.
FFD arises due to a blockage of the apocrine glands and hence sometimes is referred to as ‘sweat retention disease’. It results in nonbacterial, secondary inflammatory response to the cellular debris and secretions in the cysts. Peak incidence occurs between the ages of 13 and 35 years and there is primarily a greater prevalence among women as opposed to men and children, who may sometimes, be affected.
FFD is characterized by pruritic bumps surrounding hair follicles in regions such as the nipples, underarms and/ or groin. These areas are prone to conditions of humidity, heat, friction and stress, which lead to the development of the lesions that often appear suddenly. The itching is so severe in most patients that it disturbs the sleep.
Very few patients are asymptomatic. Moreover, many patients note a reduction in or even absence of sweating after the onset of itch and there has been no reported alleviation of symptoms with the altering of antiperspirants.
Pathophysiology of FFD
The exact etiology of FFD is unknown; however, it is limited to the skin only. Predisposing factors that are thought to play a role in the pathogenesis of FFD include emotional and/ or hormonal influences and changes in the components of sweat. For reasons that are not clear, a scaly plug in the hair follicle blocks the apocrine sweat glands.
The intense itching associated with FFD is as a direct consequence of the rupturing of the glands and the leakage of cellular debris that cause an inflammatory reaction. In addition to these aforementioned proposed factors, FFD has been reported to be associated with laser hair removal.
Treatment of FFD
The diagnosis of FFD is based primarily on patient history and the clinical appearance of the rash. While there is no cure for the disease, there are several treatment regimens that are used for its control with varying degrees of success. Many FFD patients have shown disease improvement when placed on oral contraceptives.
Other successful approaches are:
- Topical retinoids
- Topical steroids
- Topical calcineurin inhibitors
- Ultraviolet light
- Hormonal therapy
- Antibiotic therapy
Some of these therapies, however, are associated with irritation and deemed by many patients as intolerable. Despite this finding, patients need to be advised about the possible need for long-term treatment, since FFD is controllable, but not curable.