Hyperkeratosis Lenticularis Perstans (Flegel’s disease)
Hyperkeratosis Lenticularis Perstans [Flegel’s disease]
Are You Confident of the Diagnosis?
What you should be alert for in the history
Patients are usually asymptomatic, but rarely can report mild itching or burning. There is a proposed autosomal dominant mode of inheritance, so inquire about a family history. Hyperkeratosis lenticularis perstans (Flegel’s disease) can rarely also be associated with endocrine disorders such as diabetes mellitus or hyperthyroidism, so a review of systems and past medical history can be helpful.
Characteristic findings on physical examination
Lesions are multiple, red-brown to grey 1-5mm papules with a disc or lens (lenticularis) shape, sometimes with surrounding erythema. The favored areas are the dorsal feet; however, distal extremities, palms and soles, pinna and oral mucosa can be involved. Rare cases report diffuse involvement. Scraping or peeling off the scale results in pin-point bleeding.
Expected results of diagnostic studies
Clinical findings paired with skin biopsy are diagnostic. Pathology is characterized by focal hyperkeratosis and parakeratosis. The epidermis is atrophic and shows hypogranulosis as well as a thinned spinous layer. The papillary dermis is edematous, contains enlarged vessels, and a lichenoid infiltrate composed of lymphocytes and histiocytes. No laboratory or imaging studies are necessary.
The differential diagnosis for hyperkeratosis lenticularis perstans includes stucco keratoses, disseminated superficial actinic porokeratosis (DSAP), and perforating disorders, such as Kyrle’s disease. The involvement of the palms and soles is unique to hyperkeratosis lenticularis perstans, and the pathology is distinictive.
Stucco keratoses do not bleed when the scale is peeled back, and will show papillomatosis on pathology. Disseminated superficial actinic porokeratosis primarily involves the lower legs and sun exposed areas, as well as having the pathognomonic coronoid lamella histologicially. Kyrle’s disease clinically has a firm central core and patholocially shows collagen being eliminated through the epidermis.
Who is at Risk for Developing this Disease?
Hyperkeratosis lenticularis perstans is a rare disorder most commonly affecting middle-aged Caucasians, with a genetic predisposition.
What is the Cause of the Disease?
The etiology of hyperkeratosis lenticularis perstans is unknown.
There is controversial data regarding absent or aberrant lamellar granules (ie, Odland bodies, membrane associated granules) as seen on electron microscopy in lesional skin contributing to the pathophysiology. The lamellar granules release lipids that are essential to the process of desquamation; without normal desquamation, hyperkeratosis characteristic of this disease develops.
Systemic Implications and Complications
There are no systemic manifestions of hyperkeratosis lenticularis perstans. There are rare reports of association with endocrine diseases, such as diabetes and hypothroidism. Complications are primarily cosmetic, as lesions are usually multiple and tend to spread proximally.
Treatment options are summarized in
Treatment options for hyperkeratosis lenticularis perstans
|Medical Treatment||Surgical Treatment||Physical Modalities|
|Topical Steroids with or without occlusion BID (class 1: clobetasol propionate 0.05% or betamethasone dipropionate 0.05%)||Liquid nitrogen||PUVA|
|Flurouracil 5% cream||Dermabrasion|
|Retinoids (tretinoin 0.1% cream)||Excision|
|Keratolytics (urea 40 or 50%, ammonium lactate 12%)|
|Vitamin D (calcipotriene 0,05%)|
Optimal Therapeutic Approach for this Disease
The lesions of hyperkeratosis lenticularis perstans are usually asymptomatic but cosmetically frustrating. Reports have noted that older lesions are more resistant to treatment than more recent lesions.
Topical treatments are a reasonable first approach. Potent topical steroids (class I) with or without occlusion can be used in a pulsed (4 x daily a week) regimen to minimize side effects of atrophy, and can be considered first-line. Fluorouracil 5% cream has been shown to provide good results with or without occlusion, usually used twice a day for at least 1 month. Topical retinoids at the highest strength tolerable have been used. A case comparing tretinoin to fluorouracil 5% cream proved the latter to be more effective.
Keratolytics such as urea at 40% of 50% twice a day or ammoniam lactate 12% twice a day may improve the rough hyperkeratotic appearance, and have minimal side effects, but do not treat the underlying inflammation. Variable reports regarding the vitamin D derivative calcipotriene 0.05% have been shown. Systemic retinoids have been reported, but justifying their harmful side effects to treat a benign asymptomatic condition is difficult.
Another reasonable approach is surgical, as it may provide symptomatic and cosmetic results. These approaches are very much dependent upon the degree of involement. If lesions are diffuse surgical options would be unreasonable. The side effect of scarring is a possibility with liquid nitrogen and dermabrasion and an absolute with excision.
Finally, short-term psoralen with ultraviolet radiation has been used in a normal psoriasis regimen. The lesions clear with relatively few treatments, however relapse gradually occurs. It is again difficult to justify the potential harmful side effects of this treatment for a benign condition.
The patient should be made aware of the chronicity of the disease and that the disorder can be difficult to treat. There is no standard treatment and symptom relief and cosmesis are the primary management goals. Patients should be aware that there is no mortality associated with the lesions and understand the risks of each therapeutic modality.
Unusual Clinical Scenarios to Consider in Patient Management
There have been rare reports of diabetes and hypothyroidism.
What is the Evidence?
Bolognia, J, Jorrizo, J, Rapini, R. Dermatology. Mosby. 2008.(Provides an overview of the clinical and pathological features and treatments.)
Pearson, L, Smith, G, Chalker, D. "Hyperkeratosis lenticularis perstans (Flegel’s disease) Case report and literature review". J Am Acad of Dermatol. vol. 16. 1987. pp. 190-5.(Provides a case of the disease treated sucessfully with topical flurouracil after 1 month. The article provides a good review of the clinical and histologic picture of hyperkeratosis lenticularis perstans as well as similar keratotic diseases.)
Cooper, S, George, S. "Flegel’s disease treated with psoralen ultraviolet A". Br. J Dermatol. vol. 142. 2000. pp. 340-2.(Case report of a patient whose lesions cleared with 11 PUVA treatments but recurred after 6 months.)
Langer, K, Zonzits, E, Konrad, K. "Hyperkeratosis lenticularis perstans (Flegel’s disease) Ultrastructural study of lesional and perilesional skin and therapeutic trial of topical tretinoin versus 5-fluorouracil". J Am Acad Dermatol. vol. 27. 1992 Nov. pp. 812-6.(This article reviews the electron microscopic finding of normal membrane coated granules in perilesional skin and their absence in lesional skin. A case with leg-to-leg comparison between tretinoin and 5-fluorouracil both applied twice a day with occlusion showed complete clearance with 5-fluorouracil after 3 months and no improvement with tretinoin.)
Sternberg-Vos, H, Van Marion, A, Frank, J, Poblete-Gutierrez, P. "Hyperkeratosis lenticularis perstans (Flegel’s disease)- successful treatment with topical corticosteroids". Int J Dermatol. vol. 47. 2008. pp. 38-41.(Case report of pulsed dosing regimen (4 days a week) of 0.05% betamethasone dipropionate clearing most lesions completely after 2 months.)
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