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.
Our purpose was to describe the clinical features and prognosis of actinic prurigo in Amerindians in Saskatchewan, Canada.
Clinical examinations, questionnaires, phototesting, and laboratory tests were used.
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.
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.
Comment In: J Am Acad Dermatol. 1997 Mar;36(3 Pt 1):504-59091504
Actinic prurigo (AP) is an idiopathic familial photodermatosis seen in American Indians. We report on 17 patients; 16 had dermatitis and one had actinic cheilitis. Ten patients had acute dermatitis and six had chronic dermatitis. The histologies of acute AP and polymorphous light eruption (PLE; limited concept) are eczematous and indistinguishable. Both show spongiosis, superficial (and sometimes deep) perivascular lymphocytic infiltrates, and papillary dermal edema. Both also show vacuolar degeneration of the basal layer. In contrast, the chronic lichenified AP lesions are associated with marked hyperkeratosis, acanthosis, elongation of the rete ridges, and tissue repair. The large lymphoid germinal centers in the lamina propria are the main features of the lip histology. Seven biopsies were positive in the basal membrane zone on direct immunofluorescent testing, four were negative, and one was inconclusive. IgM was present in six and C3 in two. These immunofluorescent results are probably not significant. Immunofluorescent testing of the lip was negative. Although it is not possible to distinguish acute AP from PLE histologically, it is possible to differentiate the two conditions when chronic AP changes are present.
Thirty-two actinic prurigo patients of Cree ancestry underwent human lymphocyte antigen (HLA) typing and were compared with 32 control subjects of Cree ancestry. We found a significantly increased frequency of HLA-A24 and Cw4 antigens and a significant decrease in the frequency of the A3 antigen in actinic prurigo patients. These HLA associations may be helpful in determining whether actinic prurigo is a distinct disease or a variant of polymorphous light eruption.
Human leukocyte antigen typing of 41 white patients with polymorphous light eruption (limited concept) showed no significant differences when compared with the typing of 51 white control subjects. We previously found that actinic prurigo, an idiopathic photodermatosis particularly associated with Amerindians, has a positive association with antigens A24 and Cw4 and a negative association with A3. We suggest, on the basis of both laboratory and clinical findings, that polymorphous light eruption (limited concept) and actinic prurigo are two different and distinct diseases.
Comment In: J Am Acad Dermatol. 1992 Apr;26(4):6581597562
Comment In: J Am Acad Dermatol. 1992 Apr;26(4):658-91597563
The use of isotretinoin over a 2-year period was retrospectively studied in Saskatchewan. The database of the Saskatchewan Prescription Drug Plan was used to obtain the names of physicians who prescribed isotretinoin as well as the names of patients for whom it was prescribed. Of the 861 such patients 161 had been instructed to use the drug for at least 4 months by 42 physicians. Questionnaires were returned by 86 of the 161 patients and 22 of the 42 physicians. The responses confirmed that isotretinoin therapy is highly effective for acne. However, at least half of the patients for whom the agent was prescribed apparently did not complete a full 4- to 5-month course of treatment, and of the 34 women (average age 28 years) who responded to the questionnaire 12 (35%) did not use a method of contraception, which is a matter of concern in view of isotretinoin's teratogenic effects.
Over the past 4 years, a number of investigators have reported findings suggestive of linkage to schizophrenia, with markers on chromosomes 13q32 and 8p21, with one recent study by Blouin et al. reporting significant linkage to these regions. As part of an ongoing genome scan, we evaluated microsatellite markers spanning chromosomes 8 and 13, for linkage to schizophrenia, in 21 extended Canadian families. Families were analyzed under autosomal dominant and recessive models, with broad and narrow definitions of schizophrenia. All models produced positive LOD scores with markers on 13q, with higher scores under the recessive models. The maximum three-point LOD scores were obtained under the recessive-broad model: 3.92 at recombination fraction (theta).1 with D13S793, under homogeneity, and 4.42 with alpha=.65 and straight theta=0 with D13S793, under heterogeneity. Positive LOD scores were also obtained, under all models, for markers on 8p. Although a maximum two-point LOD score of 3.49 was obtained under the dominant-narrow model with D8S136 at straight theta=0.1, multipoint analysis with closely flanking markers reduced the maximum LOD score in this region to 2. 13. These results provide independent significant evidence of linkage of a schizophrenia-susceptibility locus to markers on 13q32 and support the presence of a second susceptibility locus on 8p21.
42 out of 93 Saskatchewan Indians (32 female (F) and 10 male (M] with actinic prurigo were patch tested to standard series allergens between 1983 and 1987. Positive reactions were most frequently seen with nickel (3F:2M) and colophony. All 3 positive patch tests to colophony were in males. The same patients were also patch tested to extracts of 21 Saskatchewan plants and 3 Hollister-Stier plant extracts. Only 1 male and 2 females had positive patch tests. None of these 3 had rashes on the eyelids, behind the ears or under the chin. We conclude that plant contact dermatitis is unlikely to be mistaken for actinic prurigo in Saskatchewan.
To document the persistence of perioral dermatitis at dermatology clinics at University Hospital, Saskatoon, we reviewed the charts of all patients with the condition seen between January 1983 and March 1985. Patients with rosacea referred to the clinics during the same period were used as a comparison group. A total of 80 patients with perioral dermatitis and 117 patients with rosacea were seen during the study period; most were female. Those with perioral dermatitis were significantly younger and had a significantly shorter mean duration of the eruption before presentation than those with rosacea (p less than 0.001). The distribution of the lesions was different in the two groups. Sixty-eight (85%) of the patients with perioral dermatitis and 45 (38%) of those with rosacea had used topical corticosteroids, a postulated risk factor for perioral dermatitis; the use of potent topical corticosteroids was frequent in both groups. Despite continuing medical education on the dangers of chronic use of these agents for eruptions on the face, physicians continue to prescribe them.
Cites: Br Med J. 1973 May 19;2(5863):407-104703100
542 patients (330 women, 212 men) with suspected allergic contact dermatitis were patch tested to standard series allergens between January 1983 and June 1987. Positive reactions were most frequently seen with nickel (17.4%), ethylenediamine (8.7%), formaldehyde (7.4%), colophony (7.0%), potassium dichromate (6.1%) and neomycin (5.7%). Patients with dermatitis involving the legs were significantly more likely to be allergic to ethylenediamine (p = 0.01) and benzocaine (p = 0.04) than those with dermatitis not involving the legs. Neomycin allergy was not associated with dermatitis involving the legs. Patients allergic to ethylenediamine were significantly more likely to be allergic to neomycin than patients not allergic to ethylenediamine (p = 0.002).