If your cat's hair is falling out in clumps it is probably a symptom of an underlying health issue. Your veterinarian can help you determine the cause of the hair loss and offer treatment options.
Normal cat hair loss occurs year round through light shedding of individual hairs. While a cat might shed more heavily in the spring or fall, its hair should not fall out in clumps.
Ringworm is a fungal infection that affects your cat's skin. According to the book "What Your Cat Is Trying to Tell You," ringworm causes hair to fall out and leaves round bald spots on its forehead, ears and muzzle.
Caused by mites, mange is a skin condition that causes intense itching, according to the American Society for the Prevention of Cruelty to Animals. Your cat may scratch out clumps of fur from its ears and face, leaving behind patchy-looking hair.
If your cat experiences itching caused by allergies or fleas, it could be scratching at its skin often enough to cause its hair to fall out in clumps.
According to "What Your Cat Is Trying to Tell You," ringworm can be treated with antifungal medications and washes. Allergies are treated by removing the allergen from your cat's environment. The ASPCA says mange can be treated with injections and medicated shampoos, as can fleas.