PVALB and Allergy: Of note, the rate of tropomyosin allergy was higher than those of parvalbumin or collagen allergies in dogs (Fig. 5) and the levels of specific IgE to tropomyosin was higher than those to other allergenic components derived from cod, such as parvalbumin and collagen, in dogs with cod allergy (Figs. 2a and 4).