A 55-year-old Black woman presents with complaints of rough, bumpy, and itchy oval patches to her back and bilaterally on her shins (Figures 1). She noticed a sudden onset of these patches a few months prior and had attempted to manage them with an over-the-counter topical steroid and topical antihistamine. Lack of response to conservative management, enlargement of the patch on her back, and ongoing itch prompted her to seek care.
Her history is positive for well-controlled hypertension managed with hydrochlorothiazide 12.5 mg and irritable bowel syndrome with constipation managed with lubiprostone 8 µg. She takes an over-the-counter multivitamin along with a daily vitamin B complex and vitamin D supplement.
Her medical history includes a hysterectomy and left total knee replacement. Her family history is negative for skin cancers. She is a nonsmoker and nondrinker. She routinely exercises, primarily open water or pool swimming along with strength training. She denies recent issues with fever, weight loss, weight gain, nausea, vomiting, diarrhea, or any other lesions.
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Presentation and Examination
Because the patient’s symptoms occurred during the COVID-19 pandemic, she was initially assessed and treated via a telemedicine platform. Pictures were submitted, which revealed hyperkeratotic follicles. The initial plan of care included use of urea 40% and betamethasone twice a day for suspected follicular keratosis. Betamethasone was discontinued because of lack of efficacy and triamcinolone was ordered. Again, treatment response was not observed. Based on lack of response to progressively stronger topical steroids and keratolytic agents, an in-office appointment with biopsy was scheduled. Possible diagnostic considerations included folliculotropic mycosis fungoides.
Diagnosis
Comprehensive laboratory testing including antinuclear antibodies (ANA) with reflex, comprehensive metabolic panel, thyrotropin, and complete blood cell count (CBC) with differential was unremarkable. The dermatopathology microscopy identified dermis with hair follicle-filled cornified cells surrounded by fibrosis (Figure 2).2 A diagnosis of lichen spinulosus was made based on microscopy and morphology, which ruled out other possible diagnoses.
The diagnosis of lichen spinulosus, which is most commonly found in children and young adults, was confirmed by a second dermatologist.
Discussion
First described in 1883 by English dermatologist Henry Crocker, lichen spinulosus is an uncommon but benign skin condition observed most often in children and young adults.1,2 It is rarely observed in the adult population. It is observed more frequently in males than females and lacks racial or genetic predilection. Lichen spinulosus is characterized by its sandpaper feel and bumpy follicular keratolytic spines.2 Lichen spinulosus presents in round or oval patches generally 2 cm to 6 cm in diameter. The lesions are not painful but may be associated with pruritus.2 The differential diagnosis includes follicular mycosis fungoides and keratosis pilaris.
The etiology of lichen spinulosus is unknown and the condition may be associated with Crohn disease, Hodgkin disease, HIV, vitamin A deficiency, alcoholism, and exposure to lithium, gold, thallium, or diphtheria toxin.2 The paucity of information on lichen spinulosus was noted in an article published in 1990 by SJ Friedman. Dr Freidman performed an extensive literature search and identified 35 published cases of lichen spinulosus. He sought to identify etiology, diagnostic findings, and characteristics including gender predilection, age of onset, affected areas, and visual and microscopic findings, specifically its thorny appearance and “microscopic keratotic plugging of the follicular infundibulum.”3
No known cure for lichen spinulosus exists. Reports of lichen spinulosus responding to keratolytics and emollients have been published.2 Treatments may include lactic acid, salicylic acid, urea, topical retinoids, and topical steroids.3
Conclusion
Lichen spinulosus is primarily an unwanted aesthetic condition and in some instances is accompanied by pruritus. Lichen spinulosus is not known to have any untoward systemic traits, however, misdiagnosis may result in improper patient management. Thus, it is important to rule out dermatologic conditions such as follicular mycosis fungoides.
V. Jude Forbes-De La Cruz, DNP, FNP-BC, PMHNP, is a dually certified APRN who has worked at the University of Texas Medical Branch Correctional Managed Care Division since 2004.
References
1. Radcliffe-Crocker H. Diseases of the Skin: Their Description, Pathology, Diagnosis and Treatment, With Special Reference to the Skin Eruptions of Children and an Analysis of 15,000 Cases of Skin Disease. H. K. Lewis; 1888.
2. Aghighi M, Pukhalskaya T, Brickley S, Smoller B. An uncommon case of lichen spinulosus in an adult patient clinically mimicking folliculotropic mycosis fungoides. Cureus. 2020;12(6):e8572. doi:10.7759/cureus.8572.
3. Friedman SJ. Lichen spinulosus. Clinicopathologic review of thirty-five cases. J Am Acad Dermatol. 1990 Feb. 22(2 Pt 1):261-264.
