A 26-year-old woman with no history of chronic illness presented with a 5-year history of intense pruritus in both axillae, worse during hot weather, sweating, and wearing deodorant. She denied malodor, drainage, and flares with menstruation. An examination revealed hyperpigmented, monomorphous, folliculocentric papules involving both axillae (Fig 1). Histology revealed parakeratotic plugging of the follicular infundibulum; follicular spongiosis; a perifollicular, lymphohistiocytic infiltrate with scattered eosinophils; and dilated, active apocrine glands (Fig 2).
Question 1: Which is the most likely diagnosis?
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A.
Hidradenitis suppurativa
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B.
Hailey-Hailey disease
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C.
Apocrine miliaria
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D.
Candida intertrigo
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E.
Dowling-Degos disease
Answers:
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A.
Hidradenitis suppurativa – Incorrect. While hidradenitis suppurativa affects the axillae in young adults, it presents with comedones, draining sinuses, and scarring. Monomorphic papules and pruritus are unusual in hidradenitis suppurativa. Histology would show abscess formation, often with granulation tissue and fibrosis.
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B.
Hailey-Hailey disease – Incorrect. Although Hailey-Hailey disease often presents in the axillae, this patient’s lesions were folliculocentric, monomorphic papules rather than erosive plaques. In Hailey-Hailey disease, histology reveals acantholytic dyskeratosis in a dilapidated brick-wall pattern. The apocrine glands are not specifically affected.
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C.
Apocrine miliaria – Correct. Also known as Fox-Fordyce disease, apocrine miliaria results from parakeratotic plugs blocking apocrine sweat secretion with resultant extravasation and a host inflammatory response. Female patients are most commonly affected, and they present with intensely itchy, folliculocentric, and dome-shaped papules. The areolae and genital skin may also be involved. Histology shows the obstruction of the follicle by parakeratosis with an associated lymphohistiocytic infiltrate and subjacent dilated apocrine glands.1
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D.
Candida intertrigo – Incorrect. Axillary candidiasis often presents with pruritus but no specific predilection for follicles. Pustules, erythema, and satellite lesions are characteristic.
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E.
Dowling-Degos disease – Incorrect. Dowling-Degos disease often involves the axillae but presents with asymptomatic, reticulated, and hyperpigmented macules clinically and the antler-like elongation of pigmented rete ridges microscopically.
Question 2: Which of the following is the LEAST appropriate for treating this condition?
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A.
Oral glucocorticoids
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B.
Oral contraceptives
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C.
Topical steroids
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D.
Isotretinoin
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E.
Liposuction-assisted curettage
Answers:
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A.
Oral glucocorticoids – Correct. Oral steroids are not typically indicated for this condition.
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B.
Oral contraceptives – Incorrect. Oral contraceptives have shown efficacy in women with apocrine miliaria/Fox-Fordyce disease.2
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C.
Topical steroids – Incorrect. Midpotency topical steroids are effective, but the duration of therapy is limited owing to the risk of side effects, including striae formation and skin atrophy.2,3
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D.
Isotretinoin – Incorrect. Case reports suggest that there has been some success with this oral retinoid.3
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E.
Liposuction-assisted curettage – Incorrect. This has been reported as an effective treatment. Alternatively, microwave thermolysis (MiraDry, Miramar Labs Inc) may provide relief. In severe cases, surgical excision may be warranted.2, 3, 4
Question 3: Which additional histopathologic finding may assist in the diagnosis of this patient’s condition?
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A.
Intrafollicular mucin
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B.
Perifollicular scarring
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C.
Gram-positive bacteria in the follicular infundibulum
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D.
Perieccrine lymphocytes
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E.
Perifollicular xanthomatized macrophages
Answers:
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A.
Intrafollicular mucin – Incorrect. Although seen in a variety of neoplastic (eg, folliculotropic mycosis fungoides) and reactive dermatoses, follicular mucinosis does not aid in diagnosing apocrine miliaria/Fox-Fordyce disease.
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B.
Perifollicular scarring – Incorrect. This is seen in older lesions of hidradenitis suppurativa, ruptured folliculitis, and acne scarring but not typically in apocrine miliaria/Fox-Fordyce disease.
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C.
Gram-positive bacteria in the follicular infundibulum – Incorrect. This would be helpful in diagnosing bacterial folliculitis. Commensal bacteria may be seen in the dilated follicle of patients with apocrine miliaria/Fox-Fordyce disease, but their presence does not assist in the diagnosis.
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D.
Perieccrine lymphocytes – Incorrect. Apocrine glands, rather than eccrine glands, are obstructed in individuals with Fox-Fordyce disease, and inflammation at the glandular level is not commonly seen.5
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E.
Perifollicular xanthomatized macrophages – Correct. In addition to perifollicular lymphocytes, typical histiocytes, and eosinophils, macrophages with foamy cytoplasm that resemble xanthoma cells may be seen. When identified, these cells are strongly suggestive of apocrine miliaria/Fox-Fordyce disease.6
Conflicts of interest
None disclosed
Footnotes
Funding sources: None.
IRB approval status: Not applicable.
References
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