Baseline aerobiologic data of known and potentially allergenic deuteromycetes in Corpus Christi, Texas, USA, are presented concurrent with analyses of patient skin-reactivity (November 1987-October 1988 & November 1988-October 1989). Species representations of deuteromycete spores and their relative abundance were similar for two years. Three distinct groupings were discerned: Cladosporium (representing 80% of total spores) showed weekly averages predominantly in 1000-5000/m3 range; Alternaria (7.8%), Aspergillus/Penicillium (5.3%) and Torula (0.8%) at primarily 500-1000/m3 level; and Epicoccum (1.3%), Fusarium (1.3%), Nigrospora (1.3%), Stemphylium (0.6%), Drechslera (0.5%), Curvularia (0.2%), Pithomyces (0.1%) and other minor genera, mostly in 100-500/m3 range. Spore-bursts were recorded for all deuteromycetes with extreme spore-burst capture most prevalent among sporadic spores (e.g., Curvularia and Torula). Two-thirds of the 602 atopic persons were skin-test positive to 1 or more of the 10 deuteromycete extracts. Alternaria, Cladosporium, Curvularia and Epicoccum elicited highest skin-reactivities (31.2% to 32.1%), despite wide disparity in spore concentration. Twenty-seven percent of patients were positive to Nigrospora and Stemphylium. Significant paired skin-reactivities of several deuteromycetes were detected using Kendall's Tau-β correlation coefficient. Factor Analysis of skin rectivity revealed two groupings, suggestive of cross-reactivity: Factor Group 1 consisted of Curvularia, Epicoccum, Fusarium, Cladosporium, Alternaria and Aspergillus extracts (Factor Loadings 0.56 to 0.86); Factor Group 2 included Helminthosporium, Nigrospora, Penicillium, Alternaria and Stemphylium extracts (0.45 to 0.76). High inherent allergenicity, strong cross-reactivities of shared or closely related allergens, and micro-environmental factors such as exposure to uniquely high spore concentrations or bursts, may help explain the major dissimilarities between spore capture and patient sensitization in Corpus Christi.