Practice Essentials
Fox-Fordyce disease is an infrequently occurring chronic pruritic papular eruption that localizes to areas where apocrine glands are found. The etiology of Fox-Fordyce disease currently is unknown. The eponym is based on the 1902 report by G. Fox and J. Fordyce. [1]
Causes
The definite increased prevalence of Fox-Fordyce disease in women has led to an unproved theory of hormonal influences. Reports of cases of Fox-Fordyce disease in prepubertal girls are evidence against the hormonal theory. The exact pathophysiology is still unknown.
A number of factors, including (1) emotional and/or hormonal influences and (2) alterations in sweat components, have been implicated in Fox-Fordyce disease.
Fox-Fordyce disease has been reported to occur after laser hair removal. [2, 3, 4, 5, 6]
Presentation
Fox-Fordyce disease frequently appears under conditions of heat, humidity, and friction, often appearing suddenly. Many patients present after decades of symptoms.
Few patients are asymptomatic. Most patients relate pruritus that disturbs sleep.
Changing antiperspirants has not been reported to help. Some patients report diminution of sweating after the onset of symptoms.
In a study of 68 patients with Fox-Fordyce disease, Salloum et al found that the typical patient was a young woman, postmenarchal but premenopausal. One-quarter to one-third of patients were asymptomatic. The condition was bilateral in 90% of cases. While the axillae were the areas most commonly affected, the pubic region and periareolar areas were the next most frequent sites. [7]
Diagnostics
Singal et al described the dermoscopic features of Fox-Fordyce disease as including light to dark brown folliculocentric structureless areas with the absence of dermatoglyphics. Some lesions also feature hyperkeratotic follicular plugging. [8]
Histopathologic diagnosis of Fox-Fordyce disease may be very difficult with conventional sectioning. Stashower et al proposed transverse histologic sectioning as the most effective way to demonstrate diagnostic features. [9]
Diagnosis of Fox-Fordyce disease is usually made on clinical/historical grounds. Laboratory or even histopathologic tests are seldom necessary for clinicians familiar with this condition.
Also see Histologic Findings.
Treatment
See Treatment and Medication.
Consultation with a dermatologist is usually recommended in Fox-Fordyce disease.
Activity that leads to sweating is counterproductive. Swimming is the preferred form of exercise for Fox-Fordyce disease patients.
Environmental modification and hormonal therapy have not always proven to affect the course of Fox-Fordyce disease.
Advise patients of the chronicity and the possible need for long-term therapy because Fox-Fordyce disease is often controlled but not cured.
Pathophysiology
Fox-Fordyce disease is a disease of the skin alone. In 1956, Shelley and Levy proposed apocrine miliaria as the cause. [10] The observed pathophysiology is a keratin plug in the hair follicle infundibulum obstructing the apocrine acrosyringium and producing an apocrine anhidrosis. Histologically, a rupture of the apocrine excretory duct occurs, and spongiotic inflammation results. Extravasation of sweat and inflammation is postulated to cause the intense itching. Ranalletta et al found that the acrosyringium of the eccrine glands was similarly involved. [11]
In 2003, Kamada et al published a histopathologic analysis from which they concluded that the 2 types of this disease are (1) an apocrine (follicular) type and (2) an apocrine (nonfollicular) type. [12]
Epidemiology
Fox-Fordyce disease is an infrequent condition. Geographic influence is not evident. Many case reports of Fox-Fordyce disease mention heat, humidity, and stress as exacerbating factors. Reports of Fox-Fordyce disease from the United States are the most common; however, a geographic limitation is not evident.
No racial predilection is evident for Fox-Fordyce disease.
A distinct predilection for women exists for Fox-Fordyce disease; the female-to-male ratio is 9:1.
Fox-Fordyce disease is most common in women aged 13-35 years; it is rare before or after this age.
Prognosis
Management with topical retinoids and antibiotics has brought some hope to patients with Fox-Fordyce disease for decades. Long-term follow-up studies are not available; therapy may need to be prolonged for a very long time. Acceptable therapy should be safe and relatively inexpensive.
Fox-Fordyce disease has no risk of loss of life or limb. Patients often experience severe pruritus. Therefore, the patient's quality of life may be adversely affected.
Manage Fox-Fordyce disease complications (eg, local superinfection) in the standard ways.
