A Swelling on a 4-Week-Old Puppy's Neck

We weren't able to see a photo, but any new swelling on the neck of a very young puppy should be checked by a vet soon. Young puppies can get abscesses, swollen lymph nodes and a condition called juvenile cellulitis (puppy strangles), which causes swollen glands under the jaw and on the neck, often with swelling of the face and sores. It needs prompt treatment, and very young puppies can get sick quickly.

Worms in the mother are unlikely to cause a lump on a puppy's neck, but they matter for a different reason. Roundworms and hookworms pass from mothers to puppies before birth and through milk, so the whole litter usually needs to be dewormed on a regular schedule your vet sets.

Take the puppy to a vet promptly, and go right away if it stops nursing, seems weak or quiet, has a fever, or the swelling grows quickly. See swollen lymph nodes in dogs and worms in dogs.

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