Fleas are the common cause of allergic reaction and skin rashes and generally are present in areas with pets. Pets are greatly troubled by flea infestation as adult flea feasts upon the blood of your pet. Also, if not controlled, fleas can even start feeding on human blood causing bites, rashes and allergic reaction. Many newly-constructed properties too are infected by fleas. Fleas are flat and do not have wings but can jump to find their host and begin feeding on their blood. They seek warm-blooded hosts and transfer fatal diseases between cats, dogs and humans.