Flegel originally described hyperkeratosis lenticularis perstans (HLP) in 1958 as red-brown papules with horny scales of irregular outline measuring 1-5 mm in diameter and up to 1 mm in depth.  Lesions are located primarily on the dorsal feet and lower legs, with a decreasing likelihood of manifestation proximally. Most cases have been reported in Europe.
No instigating factor has been identified clearly; some investigators have implicated UV light. However, in one case report, evidence of Borrelia infection (Borrelia burgdorferi and Borrelia garinii) was found using DNA sequencing in fresh tissue and blood from a patient with hyperkeratosis lenticularis perstans, without clinical evidence of Lyme borreliosis.  Ultrastructurally, a loss or decreased number of membrane-coating granules (also termed Odland bodies) has been reported. Membrane-coating granules are influential in the normal process of desquamation. A decrease, malformation, or absence of these membrane-coating granules may result in decreased desquamation of the stratum corneum, retention hyperkeratosis, and clinically keratotic hyperkeratosis lenticularis perstans lesions. Some authors have suggested that a cell-mediated cytotoxicity against epithelial cells may be involved in the pathogenesis of hyperkeratosis lenticularis perstans.
No data exist on incidence or prevalence of this disease. Hyperkeratosis lenticularis perstans (Flegel disease) likely has both a familial and nonfamilial variant, since several reports have postulated both an autosomal dominant and a sporadic mode of inheritance. 
Most cases have been reported in Europe. International incidence is similar to that seen in the United States.
Hyperkeratosis lenticularis perstans does not have a race predilection, although it has mostly been reported in the white population.
No sex predilection is apparent.
Hyperkeratosis lenticularis perstans reportedly occurs most commonly in mid-to-older age groups; however, reports exist of hyperkeratosis lenticularis perstans occurring in patients as young as 13 years.
Except for the possibility that lesions may progress slowly and involve more proximal sites, prognosis for hyperkeratosis lenticularis perstans (Flegel disease) is excellent. No mortality has been reported.
What would you like to print?