Children Monosensitized to Can f 5 Show Different Reactions to Male and Female Dog Allergen Extract Provocation: A Randomized Controlled Trial

BACKGROUND: Dog dander consists of several allergenic molecules including Can f 5, which is a protein expressed in the prostate of male dogs.

OBJECTIVE: To investigate whether children monosensitized to Can f 5 show different reactions to provocation tests with male versus female dog dander in a double-blind randomized clinical trial.

METHODS: Twenty-two children (15-18 years) with a history of dog sensitization were enrolled from the COpenhagen Prospective Studies on Asthma in Childhood2000 mother-child cohort. Skin prick test, specific IgE levels to dog dander (e5), and dog components Can f 1, 2, 3, and 5 were first assessed. We subsequently performed skin prick test and conjunctival allergen provocation test using dog dander collected separately from male and female dogs.

RESULTS: Seven of the 22 children were monosensitized to Can f 5. Eight were sensitized to a mix of the dog components, and 7 were no longer sensitized to dog. Of the children monosensitized to Can f 5, all had a positive skin prick test result to male dog extract and 1 of 7 was also positive to female dog extract (P = .01). Furthermore, 5 of 7 had a positive conjunctival allergen provocation test result to male dog extract and 1 of 7 also reacted to the female dog extract (P = .03). There was no difference between reactions to male and female dog extract provocation in children sensitized to a mix of the dog components.

CONCLUSIONS: Children monosensitized to Can f 5 show different reactions to male and female dog extract provocation using both skin prick test and conjunctival allergen provocation test, suggesting tolerance to female dogs.