No, Haws syndrome itself is rarely deadly, but the stomach illness linked with it can turn dangerous if dehydration or infection takes hold.
When a cat’s third eyelids slide up in both eyes, it looks scary. Many owners spot it right after a bout of loose stool or a day where their cat eats less. The eyes often look calm, yet the pale membranes stay up like a curtain.
That pattern can fit Haws syndrome. The goal is to treat it like a clue, not a standalone eye disease. You want to rule out painful eye problems, then figure out what’s upsetting the body, most often the gut.
What Haws Syndrome Is
Haws syndrome is a bilateral rise of the third eyelids (nictitating membranes). In many cases the eye surface looks normal: little redness, little discharge, no squinting, and pupils that match in size. Cats may seem mostly themselves, or they may have diarrhea, vomiting, lower appetite, or mild tiredness.
Veterinary sources describe Haws syndrome as a change in nerve tone affecting the third eyelid position, rather than damage inside the eyeball. The trigger is still being studied, with gastrointestinal disturbance appearing often in reported cases.
Can Cats Die From Haws Syndrome? What The Evidence Suggests
Most cats recover with time and care aimed at the underlying cause. A 2024 study in Veterinary Record described Haws syndrome cases where the third eyelids returned to normal over a wide range of days, with an average a bit over a month.
Death from “just Haws syndrome” is not what vets worry about. The concern is what came with it: ongoing diarrhea, fluid loss, a contagious gut infection in a kitten, parasite burden, pancreatitis, or other illnesses that can dehydrate a cat or drain energy fast. The eyelids can be the first thing you notice, then the rest of the picture shows up over the next day or two.
Think of it this way:
- Haws syndrome is usually temporary.
- The illness that triggered it can be mild or serious.
- Your job is to sort which one you’re dealing with.
Why The Third Eyelids Rise In Both Eyes
The third eyelid helps protect and lubricate the eye. Its position depends on smooth muscle tone and nerve input. When a cat is unwell, losing weight, dehydrated, or dealing with intestinal irritation, that tone can shift and the membranes can show.
Research is still evolving, yet newer papers keep linking Haws syndrome with digestive upset. A 2025 case series on PubMed Central describes cats with Haws syndrome managed with a gastrointestinal diet, and it reports that ocular signs resolved in the cats over time.
Signs That Match Haws Syndrome
Haws syndrome tends to look like “quiet eyes, raised third eyelids.” Common features include:
- Both third eyelids are raised, often in a similar way on each side.
- The cat keeps the eyes open and is not rubbing them much.
- Pupils look equal in size.
- Stool may be loose, or appetite may dip.
Veterinary Partner (VIN) has a clinician-reviewed overview that matches this description and summarizes the typical course: Haws Syndrome in Cats (VIN).
When It’s Probably Not Haws Syndrome
Many other problems can make a third eyelid show. Some need fast care. Use the whole picture, not just the eyelid position.
Eye Pain Or Injury
Squinting, holding an eye shut, pawing at the face, heavy tearing, or sudden light sensitivity points toward pain. Corneal ulcers and scratches can worsen quickly.
Horner’s Syndrome
Horner’s syndrome often causes a droopy upper lid, a smaller pupil, and a sunken look to the eye, often on one side. VCA’s client resource on Horner’s mentions “Haw’s paralysis” as a look-alike pattern tied to intestinal irritation and notes that the third eyelids may stay up for weeks: Horner’s syndrome in cats (VCA).
Dehydration And Rapid Weight Loss
Dehydration can make the eyes look sunken and the third eyelids more visible. If your cat has had frequent diarrhea, repeated vomiting, or low water intake, act sooner rather than later.
Taking A Closer Look At Haws Syndrome In Cats With Gut Signs
If loose stool shows up around the same time as raised third eyelids, vets often start with hydration status, abdominal feel, temperature, and a tight history: recent diet changes, new treats, outdoor hunting, new pets in the home, boarding, or exposure to other cats.
Parasites and contagious infections sit high on the list in kittens, new rescues, and multi-cat homes. In the 2024 study in Veterinary Record, some cats developed the condition after a new kitten arrived, which lines up with a transmissible trigger in some settings.
Haws Syndrome Vs Other Causes Of Third Eyelid Rise
The third eyelid is a symptom, not a diagnosis. This comparison helps you decide how fast to act.
| What You See | What It Can Point To | How Fast To Act |
|---|---|---|
| Both third eyelids up, eyes calm, pupils equal | Haws syndrome, often linked with gut upset | Book a vet visit soon; same day if your cat looks unwell |
| One eye squinting, tearing, rubbing | Corneal ulcer, scratch, foreign body | Same day |
| One eye: small pupil, droopy lid, sunken look | Horner’s syndrome, ear or nerve issue | Vet visit soon; urgent if trauma is possible |
| Third eyelids up plus thick discharge or red conjunctiva | Conjunctivitis, upper respiratory infection | Vet visit soon |
| Third eyelids up plus repeated vomiting or frequent diarrhea | Dehydration, electrolyte loss, GI disease | Same day if intake drops or stool is constant |
| Third eyelids up plus marked weakness or collapse | Serious systemic illness | Emergency |
| Red “cherry” mass at inner corner | Prolapsed third-eyelid gland (uncommon in cats) | Vet visit soon |
What A Vet May Do At The Appointment
Most vets aim to answer two questions: “Is there eye pain?” and “What body issue might be driving this?” A typical plan can include:
Eye Checks
- Fluorescein stain to rule out corneal ulcers.
- Pupil and eyelid reflex checks to separate Haws-type patterns from Horner-type patterns.
- Basic eye surface exam for discharge, irritation, or trauma.
Gut And Whole-Body Checks
- Fecal testing for parasites or protozoa when stool is loose.
- Bloodwork when appetite is poor, vomiting continues, or dehydration is present.
- Imaging if belly pain, weight loss, or a mass is suspected.
Care That Tends To Help
There is no single drop that “fixes” Haws syndrome. Care is aimed at the trigger while the third eyelids settle back down.
- Fluids: Hydration support can be the turning point when diarrhea is ongoing. Some cats need subcutaneous fluids or IV fluids, based on exam findings.
- Parasite treatment: If testing finds worms or protozoa, treatment is targeted. In young cats with risk factors, a vet may still treat based on history.
- Diet reset: A vet-approved gastrointestinal diet for a short stretch can help stool firm up, then the diet is adjusted based on response.
- Eye meds only when needed: If the cornea is healthy and there’s no infection, the eyelid rise often needs no direct eye treatment.
How Long It Can Last
Many cats improve over a few weeks. Published reports show a range, and some cats take longer. In the 2024 Veterinary Record paper, protrusion persisted from 12 to 95 days in that group.
If there’s no change after several weeks, or new signs show up, book a recheck. Persistence can mean the trigger is still active, or the diagnosis needs a second look.
Home Monitoring That Helps You Catch Trouble Early
Once a vet has ruled out eye pain and serious disease, home tracking can keep you ahead of a slide. Focus on what you can measure day to day.
| What To Track | What “Better” Looks Like | Call The Vet If You See |
|---|---|---|
| Stool | Fewer trips, stool firming up | Blood, black stool, diarrhea that keeps going |
| Water And Urine | Normal drinking, normal urine clumps | Dry gums, little urine, weakness |
| Appetite | Eating regular meals again | Skipping meals for a day, repeated vomiting |
| Eye Comfort | Eyes open, no squinting, eyelids slowly lowering | Squinting, rubbing, sudden redness |
| Energy | Normal movement and interest | Hiding, wobbliness, collapse |
| Breathing | Normal breathing at rest | Open-mouth breathing, fast breathing at rest |
Red Flags That Mean Go Now
- Repeated vomiting, or vomiting plus diarrhea in a kitten.
- Refusing water, or signs of dehydration.
- Collapse, severe weakness, or a cat that can’t stand.
- Eye pain signs: squinting, holding an eye shut, pawing.
- Breathing trouble, pale gums, or a swollen belly.
Reducing The Odds Of Seeing It Again
- Keep parasite prevention current for your cat’s lifestyle.
- Change foods slowly over about a week.
- Avoid sudden treat binges and rich table food.
- In multi-cat homes, isolate new cats until stool is normal and a vet check is done.
- If loose stool keeps returning, ask your vet about a plan for chronic GI workup.
Most owners walk away from Haws syndrome with two lessons: the eyes can flag gut trouble, and a calm eye surface does not mean you should skip the vet. A prompt check, hydration support when needed, and a clear plan for the diarrhea are what keep this from turning into a bigger problem.
References & Sources
- Veterinary Record (Wiley/BVA Journals).“Clinicopathological findings in cats with haws syndrome.”Describes clinical features and reported duration range for third eyelid protrusion.
- PubMed Central (NCBI).“Management of Haws Syndrome in Cats With Gastrointestinal Diet: A Case Series.”Case series linking Haws syndrome with GI signs and reporting resolution of ocular signs over time.
- Veterinary Partner (VIN).“Haws Syndrome in Cats.”Clinician-reviewed overview of presentation and typical course.
- VCA Animal Hospitals.“Horner’s Syndrome in Cats.”Explains Horner’s signs and notes Haw’s-type third eyelid elevation tied to intestinal irritation.