The answer to 'why is my flea swarms' is that flea infestations are typically caused by pets bringing fleas into the home. Fleas can reproduce quickly, leading to large populations that swarm throughout your house. Common symptoms include seeing fleas on your pets, feeling them jump on you, and finding flea dirt (flea droppings) in your home.
To solve a flea problem, you'll need to treat both your pets and your home. Start by using a flea prevention medication on your pets, then thoroughly vacuum and clean your home to remove flea eggs and larvae. You may also need to treat your yard and apply a residual insecticide inside your home. If the infestation is severe or persistent, it's best to call a professional pest control technician who can use more powerful treatments to eliminate the fleas.