Diffuse, hyperpigmented nonerythematous papules: Disseminate and recurrent infundibulofolliculitis

Case

A 33-year-old Black male initially presented to care due to persistently pruritic papules on his neck, trunk (both chest and back), and upper and lower extremities that had been present for a few months. The patient was previously diagnosed with eczema that had been treated with tacrolimus. He has no other relevant medical conditions or allergies. He has no family history of skin conditions. His initial physical examination was significant for diffuse, hyperpigmented, nonerythematous papules, as well as hyperpigmented plaques on his bilateral thighs (Fig 1), and he was assessed to have keratosis pilaris (KP). He was treated with urea 20% cream applied twice daily, tacrolimus 0.1% cream applied twice daily, and clindamycin solution applied twice daily for 2 weeks. Two months after initiation of treatment, his examination was significant for folliculocentric pigmented papules on the posterior neck and abdomen, as well as 3 to 4 firm, hyperpigmented papules less than 3 mm on the thighs. A punch biopsy of the abdomen was performed, which was significant for lymphocytic perifolliculitis (Fig 2). The epidermis also showed mild spongiosis and a scant perivascular lymphocytic infiltrate (Fig 2). No adnexal plugging was noted.

Fig 1.

Disseminate and recurrent infundibulofolliculitis (DRIF) clinical presentation. Figures A, and B are from the initial clinical visit and are of the right thigh and right arm, respectively. Figures C, and D are from a follow-up visit and are of the right lower abdomen and the upper abdomen, respectively.

Fig 2.

The hematoxylin and eosin-stained tissue shows sections of an adnexa with a perifollicular lymphocytic infiltrate (40×, 100×, and 200× magnification).

Question: What is the most likely diagnosis?

• A.KP
• B.Disseminate and recurrent infundibulofolliculitis (DRIF)
• C.Pityrosporum folliculitis
• D.Follicular eczema
• E.Lichen simplex chronicus

Discussion

Correct answer: B. DRIF.

DRIF is an uncommon condition featuring skin-colored, sometimes pruritic, recurrent or persistent, follicular papules.¹ These papules are most commonly seen on the trunk and extremities.¹ On histology, all cases of DRIF demonstrate a lymphocytic perifollicular infiltrate around the infundibular part of the follicle, which is a central diagnostic feature.¹ Other features, such as spongiosis, exocytosis, and follicular dilation, are variable.¹ Unlike in KP, the patient in this case did not show any evidence of plugging in the adnexa. The etiology of DRIF remains unknown.²

DRIF is typically self-limiting, and some patients have resolution of papules without treatment.³ Treatment of DRIF is not well established, and largely based on case reports.¹ Treatment strategies with reported benefit include doxycycline, vitamin A, isotretinoin, topical steroids, topical calcineurin inhibitors, fluocinonide cream, psoralen + ultraviolet A therapy, and narrow-band ultraviolet B therapy + tacrolimus.^1,2 Keratolytics, antihistamines, and intralesional steroids have been reported as ineffective.⁴ Ultimately, this patient was switched to fluocinonide 0.05% applied twice a day, clindamycin solution, and urea on his hands and ammonium lactate on his abdomen and legs. Though 1 prior case report discussed no symptomatic benefit from 30% urea in a single patient, it did appear to help our patient with symptom control.⁵ Three months after starting fluocinonide, the papules had resolved, leaving residual hyperpigmented macules on his bilateral lower extremities.

Conflicts of interest

None disclosed.