How do u know the differance between flea allergy and puppy mange? When Lilly was at the vet they said they wanted to keep an eye on the "thinning" hair on her forehead and may do a skin scrape in a couple weeks. There is no hair on her belly and very little on her chest now there is just a very thin amt of hair on her neck,very little. The rest of her coat is thick black and velvety The vet said she did have fleas, she was groomed and treated for fleas, they said she could be allergic. I also talked to the lady I got her from and she said Lilly's mother was highly allergic to fleas and ticks it would even cause her to have seizures. My mom keeps telling me that chihuahua's sometimes have little to no hair on tummy and chest??? I know she has several moles with old man wiskers coming out which is all Chihuahua LOL any suggestions? I know I'll find out for sure at her next vet visit in 2 weeks but if it is puppy mange can it hurt her????