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DogCatInfectious

Fleas and flea allergy

Itching, chewing near the tail base, crusts and hair loss may accompany fleas or allergy to flea saliva.

Veterinary assessment needed

Go to a clinic immediately if

  • A puppy or kitten becomes profoundly weak, has pale gums, rapid breathing or collapses
Contact a veterinary clinic

Possible signs

  • Itching at the tail base, chewing, crusts, black specks or hair loss
  • Fleas may not be visible, but black specks can leave a reddish stain when placed on damp white paper

Contact a veterinarian today if

  • Seek same-day care if skin produces pus, is very painful or a small animal becomes unusually weak and pale

What it is

A single flea can trigger intense allergic itch. Most of the flea life cycle is in the environment, so removing visible fleas from one pet is not enough.

What to expect at the veterinarian

The veterinarian will assess the skin, flea evidence, secondary infection and other causes of itch, then choose a product safe for the species, age and weight.

Sources

Updated: 26 Oct 2026

Important information

This guide does not diagnose and does not replace veterinary advice.

Do not give human medicines, leftover antibiotics or other treatment unless a veterinarian directs you. If you are unsure how urgent a sign is, contact a veterinary clinic.