Comparative incidence of allergy in the presence or absence of cancer.

Depression of the immune system may be related to cancer development. Allergic manifestations are due to enhanced immunological activity. Several authors have found lower rates of malignancy in atopic individuals. To elucidate the relationship between cancer and allergy, the prevalence of allergic manifestations was surveyed in 400 healthy controls and 400 patients with cancer. The number of allergies was significantly higher (P < 0.001) in the control group than in patients with cancer. Women were more atopic than men in both groups (P < 0.001) but skin colour did not affect the prevalence of allergies. The type of cancer was not related to any specific allergic manifestation. The results suggest that allergies occur less frequently in men than in women and less frequently in patients with cancer than in healthy controls but these relationships are complex and depend on other factors that need further investigation.