Most cases of familial PRP belong to this group. It has an early onset and runs a chronic course. It is characterized by prominent follicular hyperkeratosis, scleroderma-like changes on the palms and soles and infrequent erythema. There have also been reports of the presence of elongated follicular plugs or lichen spinulosus-type lesions. Patients tend to be resistant to standard treatments but may respond to antiretroviral therapies.
Etiology is unknown.
The diagnosis is usually made based on a correlation between clinical findings and histologic findings. Patients that have erythroderma should be monitored for electrolyte abnormalities, hypoalbuminemia, secondary bacterial infection in the skin and possible sepsis. Histologic features are not pathognomonic, but are useful to rule out other possible papulosquamous and erythrodermic disorders. The presence of acantholysis, hypergranulosis, follicular plugging and the absence of dilated capillaries and epidermal pustulation may help distinguish PRP from psoriasis. Features on electron microscopy include a decreased number of keratin filaments and desmosomes, enlarged intercellular spaces, parakeratosis with lipid-like vacuoles, large numbers of lamellar granules and a focal split in the basal lamina at the dermal epidermal junction.