Allergy to animals is the second most common source of indoor allergens in the UK and can aggravate other allergies.
Although the allergens are not in the animals' fur (contrary to what many people think), their coats can be very good "transporters" of allergens.
Once dried these allergens form small particles and are then collectively referred to as animal dander. Exposure to animal allergens usually occurs through breathing in these particles of animal dander containing the allergens. The most common are from cats; the most potent from horses and small rodents.