A 32-year-old man presents with multiple rough, crusted, itchy, malodorous skin papules on the chest, back and forehead.Further examination reveals flat wart-like papules on the dorsa of the feet and hands. The patient’s nails are chipped and have longitudinal ridges. Family history is not available, as the patient was adopted as a child.What’s your diagnosis?Submit your answer, and then read the full explanation below. If you like this activity or have a suggestion, tell us about it in the comment box at the bottom of the page.
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Keratosis follicularis, also known as Darier disease, is an autosomal dominant genodermatosis caused by mutations in the ATP2A2 gene that results in altered keratinization of the epidermis, nails and mucous membranes.
First reported in 1889, independently by Darier and White, the genetic nature of the disease was realized when it was observed in an affected mother and daughter. Keratosis follicularis is a chronic, unremitting skin disorder that occurs worldwide, with prevalence ranging from one case in 30,000 in Scotland to one case in 100,000 in Denmark.
The disorder is not present at birth and usually manifests in the first or second decade of life, but has been observed in patients as old as 70 years.
Affected skin areas are pruritic and can be painful, and the appearance and odor of the lesions may pose psychosocial problems for the patient.
Lesions first appear as skin colored papules that develop a scaly yellowish to tan, rough-textured crust. The lesions can become thick, forming plaques and hypertrophic warty masses. Keratosis follicularis typically affects the seborrheic areas of the body, including the chest, back, ears, nasolabial folds, forehead, scalp and groin.
About 95% of patients experience flat wart-like papules on the hands, with some experiencing punctate keratosis, palmar pits and hemorrhagic macules.
Nail changes including V-shaped scalloping, subungual thickening, longitudinal ridges, and the development of red and white lines can be important diagnostic clues.
About 15% of patients develop oral “cobblestone” lesions on the mucosae of the cheeks, hard and soft palate and gums.
Common complications and causes of exacerbation include cutaneous bacterial and viral infections, with keratosis follicularis patients particularly susceptible to herpes simplexvirus and poxvirus infections.
Diagnosis is based on clinical appearance, histological features from skin biopsy– including acantholysis and dykeratosis — and family history. Gene sequencing to detect mutations in ATP2A2 can confirm diagnosis.
Treatment for keratosis follicularis is with topical and systemic retinoids. Topical options include adapalene, tazarotene gel 0.01%, tertinoin and topical 5-fluorouracil. Oral Options include acitretin, isotretinoin and etretinate.
Botulinum toxin type A injections relieved discomforting symptoms from keratosis folicularis in the submammary area in one case report. Oral contraceptives may help manage perimenstrual flares. Oral antibiotics may be necessary in cases with secondary bacterial infection.
Limited evidence exists on the benefits of surgical techniques including dermabrasion, electrosurgery, laser ablation, photodynamic therapy and surgical excision for keratosis follicularis.
1. Freedberg IM, Isin AZ, Wolff K, et al. Fitzpatrick’s Dermatology in General Medicine (5th ed.). 1999. New York: McGraw-Hill.