Dermoscopic, skin confocal laser scanning microscopic and histopathological features of Fox-Fordyce disease: A report of three cases

[Objective] To investigate the dermoscopic, skin confocal laser scanning microscopic (CLSM) and histopathological features of Fox-Fordyce disease and to deepen the understanding of this disease. [Methods] Clinical, dermoscopic, skin CLSM and histopathological data of 3 patients with FFD were retrospectively analysed. [Results] All 3 patients were females, with mean age of 37 years and mean disease duration of 8.3 years (2 years to 20 years). Skin lesions were isolated firm pruritic follicular papules, sized 1~4 mm in diameter, in skin color, brown or yellowish, accompanied by hair thinning, on the large sweat gland-rich sites, including armpits in 2 cases, and both armpits and periumbilical area in one case. Dermoscopic features included flesh- to light brown-colored follicle-centered amorphous area with loss of dermatoglyphics and some hyperkeratotic plugs. Skin CLSM showed hyperkeratosis, parakeratosis, irregular thickening of the epidermis, dilated follicular orifices, follicular plugs, intercellular spongiotic edema in the follicular infundibulum, and scattered perivascular infiltration of inflammatory cells in the dermis. Histopathological changes included irregular thickening of the epidermis, mild hyperkeratosis and parakeratosis, follicular plugs, intercellular edema in the follicular infundibulum, infiltration of inflammatory cells and foam cells around the follicular infundibulum, mild dilatation of the sweat ducts, and sweat retention. All patients did not respond well to oral antihistamines, topical retinoic acid cream, and topical medium-strength glucocorticoid cream. [Conclusions] FFD is rare. Although a diagnosis can be made based on the special involved sites and characteristics of skin lesions in combination with dermoscopic, skin CLSM, and histopathological features, the treatment is still a challenge.