What is fading kitten syndrome and what causes it?

Ragdoll kitten being bottle fed
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Fading kitten syndrome is a broad term, referring to death or decline in the first several weeks of a kitten’s life. There are many potential causes of fading kitten syndrome, which is why it’s classified as a “syndrome” (a collection of clinical signs) and not an actual medical diagnosis. 

Fading kitten syndrome is most common in newborn kittens, during their first week of life. However, it can occur anytime between birth and weaning. The signs of fading kitten syndrome may be subtle at first, but they gradually become more severe and can lead to death if untreated.

What causes fading kitten syndrome? 

Fading kitten syndrome can have a number of potential causes. In general, these causes can be broken down into the following categories: 

  • Maternal factors: dystocia (difficult birth), mastitis (mammary gland infection), maternal neglect, or any significant illness of the mother during pregnancy or nursing 
  • Hereditary factors: cleft palates, gastrointestinal abnormalities, heart malformations, and other birth defects
  • Environmental factors: unsanitary conditions, extreme temperatures (especially low temperatures), and other environmental factors that contribute to stress or disease 
  • Infectious diseases: intestinal parasites, bacteria, viruses, protozoa
  • Neonatal isoerythrolysis: a blood type mismatch between a mother and her kittens, causing destruction of the kitten’s red blood cells 
  • Low birth weight: the “runt” of a litter

What age does fading kitten syndrome start?

Fading kitten syndrome can occur anytime between birth and weaning. Most kittens are weaned at approximately five weeks of age, so fading kitten syndrome occurs during the first five weeks of life. 

Many cases occur during the first week of life. However, there can be another increase in the risk of fading kitten syndrome at three to four weeks old. Kittens become more susceptible to infectious diseases at three to four weeks old, so fading kitten syndrome during this timeframe is often attributable to infectious disease. 

Kitten being given a check up by female vet

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How do I know if my kitten has fading kitten syndrome?

Fading kitten syndrome can cause a variety of clinical signs. These signs may be subtle at first, but they can quickly progress. 

In general, signs that may indicate fading kitten syndrome include: 

  • Weak suckling reflex 
  • Kitten not eating 
  • Failure to meet developmental milestones, compared to littermates
  • Decreased movement or coordination, compared to littermates
  • Lethargy
  • Weakness
  • Poor weight gain
  • Vomiting
  • Diarrhea
  • Sneezing
  • Discharge from the eyes or nose
  • Frequent or constant vocalization, as if in pain
  • Distended or bloated belly

If you suspect fading kitten syndrome, seek veterinary care as soon as possible. Kittens can deteriorate quickly. Their small size leaves them prone to hypothermia (low body temperature) and hypoglycemia (low blood sugar). Seek care at an emergency veterinary hospital if your regular veterinarian is closed. 

Your kitten's first vet visit will begin with a thorough physical examination. Next, the veterinarian may recommend specific tests to look for underlying causes of your kitten’s illness. These tests may include blood tests, fecal parasite examination, urinalysis, and bacterial cultures. 

Kitten looking over woman's shoulder

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Is fading kitten syndrome contagious?

Fading kitten syndrome may or may not be contagious, depending on its underlying cause. 

Contagious illnesses that may cause fading kitten syndrome include feline herpesvirus-1, feline calicivirus, Toxoplasma gondii, Isospora, Giardia, E. coli, Salmonella, intestinal worms, and others. These conditions commonly cause illness beginning at three to four weeks of age. 

If your veterinarian suspects that your kitten has a contagious illness, they will talk to you about how to minimize the risk to your kitten’s littermates and other pets in your home.

Catherine Barnette
Catherine Barnette DVM

Dr. Barnette is a graduate of the University of Florida, where she received both her B.S. in Zoology and her Doctor of Veterinary Medicine (DVM). She has 15 years of clinical experience as a small animal veterinarian, treating dogs, cats, and occasional exotic patients.

Treating fading kitten syndrome

Treatment depends on the kitten’s underlying disease. Infectious diseases may require antibiotics, antiprotozoal medications, or deworming. Birth defects may require surgical correction. A blood transfusion may be needed to treat neonatal isoerythrolysis.

Your veterinarian will also recommend treatments to support your kitten’s overall health. Your kitten may be hospitalized for intravenous (IV) fluids, oxygen therapy, and/or injectable medications. If your kitten is stable enough to be treated on an outpatient basis, you might be instructed to bottle-feed your kitten or feed them via a stomach tube. Your kitten will require a clean environment with careful temperature control and close monitoring. 

Once your kitten has made it through the acute stage of their illness, proactive care will help keep them healthy. Check out our kitten care tips for information on how to care for young kittens. 

Close up of kitten with blue eyes

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Can a kitten survive fading kitten syndrome?

If fading kitten syndrome is recognized and treated early, kittens have a higher likelihood of survival. Even with treatment, however, fading kitten syndrome can be fatal. Your kitten’s prognosis will depend on their underlying illness and whether that condition can be corrected.


Fading kitten syndrome is a serious concern in young cats, and it has a number of potential causes. In order to allow for the best possible outcomes, it’s important to monitor young kittens closely. Seek prompt veterinary care at any sign of illness, and follow your veterinarian’s recommendations regarding diagnostic testing and treatment. 

Catherine Barnette DVM

Dr. Barnette is a graduate of the University of Florida, where she received both her B.S. in Zoology and her Doctor of Veterinary Medicine (DVM). She has 15 years of clinical experience as a small animal veterinarian, treating dogs, cats, and occasional exotic patients. She now works as a freelance veterinary writer, creating educational content for veterinarians, veterinary team members, and dedicated pet owners. Dr. Barnette lives in southwest Florida with her husband and daughter (plus two cats, a dog, and a rescued dove!) and enjoys kayaking, biking, and hiking. Learn more about Dr. Barnette at www.linkedin.com/in/catherinebarnette.