My Chihuahua's Eye Is Red, Big, And Really Swollen. What Should We Do?

Your Chihuahua needs to be investigated by the vet because medical history and eye examination along with some laboratory tests are needed to have differential diagnosis. Treatment of eye swelling in dogs depends upon underlying cause. There are many conditions that can cause swelling and redness in eyes of dogs. Most common causes are

1. Insect bite
2. Conjunctivitis due to virus or bacteria
3. Foreign bodies like splinters or grass in the eyes
4. Parasites of eyelids
5. Tear duct disease
6. Problems with tear production
7. Corneal diseases

So, take your dog to vet for proper diagnosis and treatment.