Delayed hypersensitivity skin testing for assessing anergy in the mid-south

Although skin testing with ubiquitous antigens is widely employed to assess delayed hypersensitivity, little is known about the effect of geographic location on the frequency of skin test reactions to given antigens. To assess skin test reactivity in the mid-South, 82 hospitalized patients and 68 normal controls had skin tests with six antigens: histoplasmin, mumps, tuberculin purified protein derivative (PPD), Candida, Trichophyton, and streptokinase-streptodornase. Ninety-five percent of normal and 79% of hospitalized subjects without immunologically related disease reacted to at least one of the antigens. A high rate of anergy was found in a clinical setting of debilitation and malnutrition. If subjects in poor condition also were excluded, 93% of hospitalized patients reacted to at least one antigen. Rates of reactivity increased with higher concentrations of antigen. To assess anergy in the mid-South, it is recommended that patients be skin tested initially with histoplasmin, mumps, and PPD antigens. If the patient does not react to any of these, streptokinase-streptodornase and Candida albicans (Dermatophytin "O") should be applied.