Why Does My Dog Lose Hair Every Summer?

Hair loss and redness that come back every summer, especially on the belly and under the legs, point more toward seasonal allergies than mange. Pollen and grass allergies, flea allergy, and skin infections that flare in heat and humidity tend to follow the seasons, then settle down when the weather changes. Mange doesn't usually come and go with the seasons.

That said, sarcoptic mange can be mistaken for allergies for weeks or months, and demodectic mange can relapse in dogs whose immune systems are under strain. So it's worth asking your vet for a skin scraping, especially this year since it's worse than before.

Your vet can also check for fleas, bacterial or yeast infection, and hormone problems such as hypothyroidism, which can cause hair loss in adult dogs. If allergies are the cause, there are good treatments to ease the itch and prevent flare-ups, and a vet-recommended flea preventive year-round helps too. Read more about mange and the skin problems that look like it.

This is general information, not a diagnosis. Please follow your own vet's advice.