Actinic prurigo: Clinical features and HLA associations in a Canadian Inuit population

• Published in: Journal of the American Academy of Dermatology 2001-06, Vol.44 (6), p.952-956
• Main Authors: Wiseman, Marni C., Orr, Pamela H., Macdonald, Sharon M., Schroeder, Marlis L., Toole, John W.P.
• Format: Article
• Language: English
• Subjects: Adult; Age of Onset; Aged; Biological and medical sciences; Canada; Dermatology; Eye - pathology; Face - pathology; Female; Genetic Predisposition to Disease; Histocompatibility Testing; Humans; Indians, North American; Male; Medical sciences; Middle Aged; Photosensitivity Disorders - ethnology; Photosensitivity Disorders - genetics; Photosensitivity Disorders - immunology; Polymerase Chain Reaction; Prurigo - ethnology; Prurigo - genetics; Prurigo - immunology; Seasons; Skin involvement in other diseases. Miscellaneous. General aspects
• ISSN: 0190-9622; 1097-6787
• DOI: 10.1067/mjd.2001.112579

Background: Actinic prurigo (AP) is an idiopathic familial photodermatitis. AP of the Inuit is rarely reported and poorly characterized. Objective: Our purpose was to examine the clinical features and HLA associations of AP in an Inuit population. Methods: Thirty-seven Inuit subjects with AP were administered a questionnaire and underwent a cutaneous examination. Other causes of photosensitivity were excluded. HLA class I typing was performed by polymerase chain reaction and sequence-specific primers and class II typing by polymerase chain reaction and sequence-specific oligonucleotide probes. Results: Subjects were 81.1% female, 67.6% had a family history of photosensitivity, and all experienced seasonal variation. The average age at onset of photosensitivity was 29 years, and only 27% had a trend toward improvement in photosensitivity. Involvement of eyes and nonexposed skin was reported in 62.2% and 18.9% of subjects, respectively. Physical examination revealed involvement of the face (64.9%), lip (32.4%), ear (13.5%), and dorsal aspect of the hand (24.3%). HLA-DRB1*14 was present in 51.2% of subjects and 26.2% of controls (P = .022, odds ratio = 2.975). This is a previously unreported HLA association. Conclusion: AP in the Inuit is a seasonal, pruritic photodermatitis, often commencing in adulthood and worsening over time. A novel association with HLA-DRB1*14 has been discovered. Overall, this novel HLA association, the absence of HLA associations previously reported in non-Inuit populations, and clinical distinguishing features support the concept that AP in the Inuit may have a distinct immunopathogenic basis that translates into a different phenotype. It also raises the question of whether AP in the Inuit is a distinct photosensitivity disorder specific to this group that has been genetically isolated because of geographic and cultural seclusion. (J Am Acad Dermatol 2001;44:952-6.)