Peter R. Lane

Risk factors for basal cell carcinoma.

Completed questionnaires regarding suspected risk factors for basal cell carcinoma (BCC) were completed by 538 basal cell carcinoma patients and 738 age‐, sex‐, and location‐matched controls in Saskatchewan. Significant risk (actors were identified using chi2 analyses. Relative risks were subsequently computed. The following relative risks were identified: occupation of farming, 1.29; prominent freckles in childhood, 1.23; family history of skin cancer, 1.22; sunburn, 1.19; Irish, Scottish, Welsh mother, 1.19; light skin color, 1.18; red/blond hair color, 1.16; and working outdoors more than 3 hours/day in winter, 1.13: The average age of cases of BCC with a family history of skin cancer was significantly lower than cases of BCC with no family history of skin cancer (63.86 vs. 67.02 years, p = 0.018). No association was noted between BCC and psoriasis.

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.

HLA typing in actinic prurigo

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.

Risk factors for squamous cell carcinoma of the skin in Saskatchewan, Canada

Completed questionnaires regarding suspected risk factors for skin cancer were completed by 178 cases of SCC of the skin in Saskatchewan, Canada, and 284 age- sex- and location-matched controls. Significant risk factors identified using chi2 analyses were: farming, family history of skin cancer, light eye color, blond or red hair color, skin types I or II, obvious freckles in childhood, history of severe sunburn, and the use of the herbicide 2,4-Dichlorophenoxy acetic acid. The following relative risks were identified: (1) All cases of SCC of the skin and matched controls: agricultural occupation 1.49, history of severe sunburn 1.49. (2) All men with SCC of the skin and matched controls: history of severe sunburn 1.36 (3) All women with SCC of the skin and matched controls: agricultural occupation 1.83, and skin types I or II 1.48. No association was noted on our study between a history of psoriasis and development of SCC. Neither was an association between smoking and SCC found.

Lichenoid stomatitis associated with lithium carbonate

Lichenoid stomatitis has been reported in the use of a number of drugs. This is a case report of lichenoid stomatitis associated with lithium carbonate. The association between lichenoid stomatitis and lithium carbonate was confirmed by rechallenge in this patient. A number of cutaneous reactions have been reported as adverse effects of lithium therapy. Lichenoid reactions are characterized by an infiltrate of T cells. Lithium has been reported to alter T cell function in vitro.

A study of acne treatments as risk factors for skin cancer of the head and neck

Summary A retrospective questionnaire was conducted as to the risk factors for facial skin cancer with emphasis on acne and past treatments for acne, in particular use of benzoyl peroxide preparations. The response rate was 90·9% for 964 cases and 79·9% for 3856 controls. There was no association between acne and the use of any acne medication for the risk of facial skin cancer. Cases of skin cancer were significantly more likely to have used phototherapy or sunbeds than the controls (P= 0·024), and more likely to have had radiotherapy prior to diagnosis (P= 0·001). The major risk factors as determined by generalized linear interactive modelling were family history of skin cancer (odds ratio 2·68; 95% confidence interval 2·15, 3·34), light skin (1·54; 1·25, 1·89), sunburning easily (1·43; 1·16, 1·76) and Irish, Scottish, Scandinavian or German mothers (1·33; 1·11, 1·59).

HLA typing in 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.

Results of routine patch testing of 542 patients in Saskatoon, Canada

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 (l7.4%), ethyelnediamine (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 he allergic to 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).

Histopathology of actinic prurigo.

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 hyper-keratosis, 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.

Major gene segregation of actinic prurigo among north American Indians in Saskatchewan

Actinic prurigo is an idiopathic, familial photodermatosis seen especially in American Indians. Segregation analysis was performed on 12 Saskatchewan pedigrees with American Indian ancestry, comprising a total of 1,148 individuals, ascertained via probands diagnosed with actinic prurigo. Although a high degree of familial aggregation has been noted in the past and dominant inheritance has been suggested, no formal segregation analysis has been attempted. Actinic prurigo has a variable age of onset and, therefore, age at the time of censoring must be taken into account in the analysis. However, as these ages of 57% of the unaffected individuals were missing, an algorithm was devised to impute the missing ages from known birth years in the family based on the age differences among relatives and spouses. Using these imputed ages, simple dominant inheritance with incomplete penetrance and a single age of onset distribution was found. The method for imputing the ages at examination was evaluated, as was the correction for ascertainment, by using alternative methods and comparing the results. Regardless of the method used, a dominant mode of inheritance without any multifactorial component remained the best hypothesis.