What is a common sign that a flea infestation may be present?

A common sign that indicates the presence of a flea infestation is hair loss in pets. This occurs because fleas feed on the blood of their host and can cause irritation, leading to excessive scratching or grooming. The result is often bald patches or thinning fur, particularly in areas where pets can reach to scratch more easily, such as along the back, neck, or base of the tail.

Fleas also cause allergic reactions in some pets, which can exacerbate hair loss and lead to more severe skin issues. While other signs might indicate a flea problem—such as sightings of adult fleas or visible flea eggs—hair loss is a direct consequence of an infestation, making it a more telling symptom of flea activity specifically affecting pets. Thus, pet owners noticing hair loss should investigate further to confirm a flea infestation.