Actinic prurigo: clinical features and prognosis.

Background: Actinic prurigo, an idiopathic familial photodermatosis, has been described in Amerindians in Manitoba, Canada, as well as in the United States, Mexico, and South America.
Objective: Our purpose was to describe the clinical features and prognosis of actinic prurigo in Amerindians in Saskatchewan, Canada.
Methods: Clinical examinations, questionnaires, phototesting, and laboratory tests were used.
Results: We present a series of 93 Amerindian patients. The face is the most commonly involved area. A hereditary tendency, cheilitis, and pruritus are prominent features. One third of patients report some lesions, often minor, during the winter. The majority of patients phototested were sensitive to ultraviolet A light.
Conclusion: We find the age of onset of actinic prurigo to be the most important feature in determining the type of eruption and the prognosis for the patient. In general the younger ages of onset (up to 20 years of age) are associated with cheilitis and more acute eruptions and are more likely to improve over 5 years. Those who develop actinic prurigo as adults (21 years of age and older) tend to have a milder and more persistent dermatosis.