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 HLP lesions. 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. To date, all reports of HLP have been in white patients. No gender predilection appears to exist.
Lesions spread proximally at a slow rate.
HLP usually is an asymptomatic condition. Involvement of the ear pinnae, arms, palms, soles, and the oral mucosa has been reported, although these reports are rare. Removal of the scale reveals a bright red base, often with pinpoint bleeding. A localized unilateral variant has been reported. To date, the causes of HLP are unknown.