Dog allergen extracts are used to diagnose and treat allergic diseases. Mammalian allergens are present in a variety of sources, and different raw materials are used to produce allergenic extracts extracts. Those materials include dander, hair, epithelium, pelt, skin scrapings, and hides. However, dander is the most commonly used product.
Because most individuals sensitized to cats react to Fel d 1, standardized extracts to cat allergens are available, based on particular concentrations of this allergen. On the contrary, a distinctive major dog allergen recognized by the specific IgE of most dog-sensitized individuals has not been identified. Therefore, a large variety of heterogeneous products are on the market.
Several dog allergens, including Can f 1, Can f 2, and Can f 3 have been traditionally considered relevant to particular individuals sensitized to dogs, with Can f 2 (lipocalin) and Can f 3 (albumin) being responsible for cross-reactivity among mammals. More recently, other dog allergens (Can f 4, Can f 5, and Can f 6) have been identified and proven clinically relevant to particular individuals. These allergens also are responsible for cross-reactivity.
It is important to note that Can f 5 is mainly secreted by non-neutered adult male dogs. Because female and neutered dogs produce lower quantities of this allergen, it has been suggested that they could be appropriate as household pets for individuals allergic to dogs. Therefore, different types of dog allergenic extracts could be needed to properly diagnose the allergic patient.
The fact that major clinically relevant dog allergens that affect most sensitized individuals have not been identified to date, combined with the heterogeneous composition of dog raw materials is responsible for the presence of a number of products on the market with differential diagnostic value. The currently available allergenic preparations may not be suitable for immunotherapy.
The intrinsic nature of sensitization to dog allergens is unique, and consistent diagnostic tools are needed. The production of individual dog allergens is an emerging technology with applications for diagnosis and treatment to target specific patient populations.