April 1995

Familial Pityriasis Rubra Pilaris

Author Affiliations

From the Departments of Medicine, Division of Dermatology (Drs Vanderhooft, Francis, Holbrook, Dale, and Fleckman), Pediatrics, Division of Dermatology (Drs Vanderhooft and Francis), Biological Structure (Dr Holbrook), Oral Biology, Periodontics, and Biochemistry (Dr Dale), University of Washington School of Medicine and Children's Hospital and Medical Center, Seattle.

Arch Dermatol. 1995;131(4):448-453. doi:10.1001/archderm.1995.01690160076012

Background:  Familial pityriasis rubra pilaris is a rare autosomal dominant skin disorder. Four individuals from one family are described who demonstrate clinical features compatible with a diagnosis of familial pityriasis rubra pilaris. Results of light and electron microscopic, immunocytochemical, and biochemical analysis of skin biopsy specimens from three of these four individuals are presented.

Observations:  All affected individuals demonstrated erythematous scaly skin with follicular prominence and islands of sparing. Inheritance was consistent with an autosomal dominant trait. Light and electron microscopic findings were compatible with those reported in sporadic cases of pityriasis rubra pilaris. Immunocytochem- istry showed suprabasal staining with monoclonal antibody AE1. Immunoblot analysis revealed abnormal keratins with K6/16 expression, the possibility of an abnormal K14 or K16, and a 45-kd acidic keratin not normally expressed in epidermis. Because similar biochemical analyses have not been reported previously in other cases of pityriasis rubra pilaris (familial or sporadic), comparisons cannot be made.

Conclusions:  The observations suggest that the cutaneous abnormality in this family extends beyond clinical and morphological alterations to abnormalities in biochemical markers of epidermal differentiation.(Arch Dermatol. 1995;131:448-453)