Management of Haws Syndrome in Cats With Gastrointestinal Diet: A Case Series

ABSTRACT

Background

Haws syndrome (HS) in cats is characterized by bilateral protrusion of the third eyelid and ptosis, often accompanied by gastrointestinal (GI) symptoms such as diarrhea. Emerging evidence suggests disruption of the gut‐brain axis, linked to GI microbiota dysbiosis, may play a role in HS development.

Objective

To describe the clinical features and outcomes of five cats with HS managed with a gastrointestinal diet targeting presumed dysbiosis.

Methods

This study included five cats diagnosed with spontaneous HS. Each cat underwent thorough ophthalmic and physical examinations, as well as fecal Giardia testing and pharmacological testing with 1% phenylephrine. All cats were managed with Hill's Gastrointestinal Biome diet for 3 months.

Results

Ocular signs transiently resolved following topical administration of 1% phenylephrine, indicating sympathetic neuropathy. Physical examinations were unremarkable, except for diarrhea in 3/5 cats. Fecal tests for Giardia were initially positive in 4/5 cats and became negative in 3 upon recheck. GI symptoms resolved within 4 to 14 days in 2/3 cats with diarrhea, although only partial improvement was noted in one. Ocular signs resolved in all cats within 11 to 39 days and did not recur during the follow‐up period of 327 to 438 days.

Conclusion

The improvement in ocular and GI signs following dietary management with a prebiotic‐enriched gastrointestinal diet suggests that this approach may be beneficial for cats with HS, potentially by addressing underlying GI microbiota dysbiosis. However, it may be insufficient in refractory cases or when GI symptoms do not fully resolve.

1. Introduction

Haws syndrome (HS) is a relatively common condition in cats characterized by bilateral protrusion of the nictitating membrane (third eyelid) and ptosis (droopy upper eyelid), often accompanied by gastrointestinal (GI) disturbances such as diarrhea [1]. The pathogenesis of HS is poorly understood, but growing evidence suggests a link between GI microbiota dysbiosis and disruption in the gut‐brain axis [1], a bidirectional communication network connecting the enteric and central nervous systems [2]. Dysbiosis, an imbalance in the gut microbiota, can lead to systemic inflammation, altered neurotransmission, and immune dysregulation [2, 3], all of which may contribute to the clinical manifestations of HS. In fact, alterations in gut microbiota are known to influence sympathetic nervous system activity through gut–brain signaling pathways—likely mediated by metabolites such as short‐chain fatty acids—which may explain the bilateral third eyelid elevation and ptosis characteristic of ocular sympathetic neuropathy in feline HS [4, 5, 6, 7].

The gut‐brain axis has been implicated in the pathophysiology of several conditions, including neurodegenerative diseases like Parkinson's and Alzheimer's [3], as well as ocular diseases such as uveitis, glaucoma, and dry eye disease [8, 9]. As a result, targeting gut health has gained interest as a therapeutic strategy for various disorders affecting the eye [10, 11] and other organs.

This case series describes the potential therapeutic effect of a gastrointestinal prescription diet on HS, whereby correcting dysbiosis could alleviate or resolve clinical signs by restoring gut‐brain axis homeostasis.

2. Presentation of Cases

Five cats were presented with acute bilateral ptosis and third eyelid elevation, consistent with a diagnosis of HS secondary to ocular sympathetic neuropathy [1]. Each cat underwent a comprehensive physical examination (BF) that included body weight, body condition score (BCS), rectal temperature, mucous membrane and skin health assessment, abdomen and lymph node palpation, and thoracic auscultation. A board‐certified veterinary ophthalmologist (LS) then performed a detailed ophthalmic examination, which included slit‐lamp biomicroscopy (SL‐17; Kowa Company), indirect ophthalmoscopy (Keeler Vantage; Keeler Instruments), rebound tonometry (TonoVet Plus; Icare Finland), fluorescein staining of the ocular surface (AKti‐flu; AKtive), measurement of the horizontal pupil diameter in both eyes (Rexbeti digital caliper, accuracy ±0.01 mm), and photo‐documentation. Menace responses, pupillary light reflexes, Schirmer tear test‐1 values, intraocular pressures, and fundus appearance were within normal limits in all cats, consistent with findings from a recent study on HS [1]. The only consistent abnormalities were bilateral third eyelid elevation and mild ptosis. Ocular sympathetic neuropathy was confirmed by the application of topical 1% phenylephrine in both eyes. In all cats, the administration of 1% phenylephrine Efrin‐10 (Fischer Pharmaceuticals), diluted 1:10 with sterile saline, resulted in a rapid (within 10–15 min) but temporary (lasting 2–4 h) resolution of ocular signs, supporting a postganglionic sympathetic lesion and consistent with previous reports [1]. A fecal sample was collected for Giardia duodenalis antigen detection using an ELISA‐based test (Immuno Run, Biogal‐Galed Labs). Following the diagnosis of HS, each cat was prescribed Hill's Gastrointestinal Biome diet for a 3‐month duration. One month after starting the diet, a follow‐up fecal test was performed to assess for Giardia duodenalis. No deworming or antiprotozoal medications were administered to any cat during the study period. This retrospective study reviewed cases of client‐owned cats treated with standard‐of‐care diagnostics and therapy. No experimental procedures were performed, and ethical approval was not required. Owner consent was obtained in accordance with institutional and GERVO guidelines.

2.1. Case 1

An 8‐month‐old intact male Domestic Shorthair cat, fully vaccinated and dewormed, from an indoor multi‐cat household (the same household as Cases 2 and 3) and exclusively fed Orijen Original Cat food, presented with bilateral third eyelid protrusion and ptosis, without gastrointestinal signs (Figure 1A). The cat was brought to the Veterinary Teaching Hospital of the Koret School of Veterinary Medicine (Hebrew University of Jerusalem, Israel) on the first day these ocular signs appeared. While diarrhea was not present at the time of examination, the cat had experienced intermittently soft to watery stools over the prior 2 months. Two days after presentation, the cat developed diarrhea, and a fecal test from the initial visit confirmed Giardia duodenalis infection. Upon starting the Gastrointestinal Biome diet, the ocular signs resolved within 20 days (Figure 1B), and the GI signs improved within 14 days. A repeat fecal test performed 1 month after the initial presentation was negative for Giardia. Although the watery diarrhea resolved, the stool consistency remained soft. By the last follow‐up (Day 438), the cat continued to experience chronic enteropathy. Despite multiple therapeutic trials, including fecal microbiota transplantation, probiotic supplementation with Nutrafibre (NutraVet, Bolton, England; 400 g once daily long‐term), hypoallergenic diet (Purina Hypoallergenic for 3 months), oral metronidazole (15 mg/kg twice daily for 14 days), and routine deworming (Drontal Bayer Animal Health; one tablet every 3 months), the best clinical response was observed with the GI Biome diet, which resulted in improved stool consistency (mildly soft) and maintained good body condition.

FIGURE 1.

Clinical images of five cats with haws syndrome before (A, C, E, G, I) and 11–39 days after (B, D, F, H, J) transitioning to a gastrointestinal diet with prebiotics (Hill's GI Biome).

2.2. Case 2

A 2.5‐year‐old spayed female mixed breed cat, fully vaccinated and dewormed, from an indoor multi‐cat household and exclusively fed Orijen Original Cat food, presented 1 day following the appearance of bilateral third eyelid protrusion and ptosis, without GI symptoms (Figure 1C). A fecal test was positive for Giardia. Following the initiation of the Gastrointestinal Biome diet, the ocular signs resolved within 31 days (Figure 1D). A repeat fecal test performed 1 month after the initial presentation was negative for Giardia.

2.3. Case 3

A 2.5‐year‐old spayed female Domestic Shorthair cat, fully vaccinated and dewormed, from an indoor multi‐cat household, was exclusively fed Orijen Original Cat food, presented 1 day following the appearance of bilateral third eyelid protrusion and ptosis, without GI symptoms (Figure 1E). The cat tested positive for Giardia. After starting the Gastrointestinal Biome diet, the ocular signs resolved within 39 days (Figure 1F). A repeat fecal test performed 1 month after the initial presentation was negative for Giardia.

2.4. Case 4

A 2.5‐year‐old castrated male Domestic Shorthair cat, fully vaccinated and dewormed, from an indoor/outdoor single‐cat household, presented with bilateral third eyelid protrusion and ptosis, as well as diarrhea (Figure 1G). The cat was brought to our clinic 1 day after the onset of ocular signs and 3 days after the onset of GI symptoms. A fecal test was positive for Giardia, and the cat was fed exclusively La'cat diet. After initiating the GI diet, the ocular signs resolved within 11 days, and the GI symptoms resolved within 4 days (Figure 1H). A repeat fecal test performed 1 month after the initial presentation was positive for Giardia.

2.5. Case 5

A 3‐year‐old castrated male Domestic Shorthair cat, fully vaccinated and dewormed, from an indoor multi‐cat household, presented 5 days following the appearance of bilateral third eyelid protrusion and ptosis (Figure 1I), and 3 days following the onset of diarrhea. A fecal test was negative for Giardia, and the cat had been exclusively on Premio Supreme kitten formula. The ocular signs resolved within 17 days after starting the GI diet (Figure 1J), and the GI symptoms resolved within 5 days. A repeat fecal test performed 1 month after the initial presentation was negative for Giardia.

In Cases 1–3 (cats from the same household), the information provided above describes a recurrent episode of HS. These cats had previously experienced an episode of HS that resolved 179, 156, and 182 days earlier, respectively, which were managed differently and are described in detail in a separate study [1]. Approximately six months later, HS recurred in all three cats on the same day, and this second episode was managed with the gastrointestinal diet evaluated herein. In the current case series, none of the five cats exhibited a recurrence of HS during a follow‐up period that ranged from 327 to 438 days (mean ± SD, 398 ± 55 days; median 436 days).

3. Discussion

In this case series, five cats diagnosed with HS demonstrated resolution in ocular signs following dietary management with a prebiotic‐enriched gastrointestinal diet. The specialized diet also improved GI signs in the 3/5 cats that presented with concurrent diarrhea, and Giardia became undetectable in 3/4 cats that initially tested positive. At the time of the final follow‐up (327 to 438 days), none of the cats exhibited a recurrence of HS.

In a recent study conducted by our group, clinical signs of HS resolved in 9 out of 10 cats within 12–95 days (37 ± 23 days) following broad‐spectrum deworming, with or without adjunctive antibiotic therapy, as compared to 11–39 days (24 ± 11 days) in the current study [1]. However, three cats from the previous report experienced recurrence 156–182 days later (Cases 1–3 in this study). In these three cats, the duration of HS resolution during the first and second episodes was comparable (12–38 days vs. 20–39 days, respectively), despite utilizing a ‘drug‐free’ approach in the second/recurrent episode. Additionally, all three cats tested negative for Giardia within 1 month of starting the new gastrointestinal diet and remain free of ocular symptoms at the time of manuscript publication (438 days). When comparing both studies, the GI Biome diet was associated with a high resolution rate (5/5 cats) and no recurrence during the follow‐up period (327–438 days), compared to a 4/9 recurrence rate in our previous report (follow‐up 154–278 days) [1]. These findings support the notion that restoring gut microbiota balance via targeted nutritional therapy may address the root cause of HS more effectively than treatments aimed solely at eliminating specific GI pathogens.

The selected diet (Hill's GI Biome) contains a proprietary blend of prebiotic fibers that supports the growth of beneficial bacteria and releases fiber‐bound polyphenols with antioxidant and anti‐inflammatory properties to nourish the GI tract [12, 13]. The diet was administered to our feline patients for 3 months, based on general nutritional guidelines for GI disorders and dysbiosis in companion animals [14]. We propose that the Hill's Biome diet facilitated clinical resolution of HS and prevented recurrence by correcting microbiota dysbiosis and enhancing gut‐brain axis function, which in HS may be disrupted by gastrointestinal dysbiosis altering autonomic signaling to the eye [1]. The growth of beneficial bacteria promoted by the diet may have helped treat Giardia or other GI pathogen(s), potentially by competing for nutrients and adhesion sites, producing antimicrobial substances, and modulating immune defenses [15, 16]. While some cats tested positive for Giardia duodenalis at presentation, these findings should be interpreted cautiously, as prior treatments and diagnostic limitations may have influenced results. Dietary management cannot be considered a substitute for antiparasitic therapy, and Giardia was not the main focus of this study.

The incomplete resolution of diarrhea in one of the three cats with GI signs suggests that dietary management alone may be insufficient in certain cases, particularly those with advanced GI microbiota dysbiosis, which may contribute to chronic enteropathy. Alternative therapeutic strategies, such as probiotic supplementation or fecal transplantation, may be necessary to restore GI homeostasis and fully resolve clinical symptoms in selected cases [17, 18]. Fecal transplantation has been explored in veterinary medicine as a means to re‐establish a balanced gut microbiota and may represent a viable option in refractory cases [18]. In this study, fecal transplantation was performed in one cat (Case #1) but did not lead to improvement in fecal consistency. Probiotic supplementation has shown benefits in cats by modulating the gut microbiota and enhancing mucosal immunity, which could help in cases where diet alone is not effective [17].

Despite these preliminary findings, several limitations of this case series should be acknowledged. The small sample size restricts the generalizability of the results for cats with HS, as the etiopathogenesis of HS may differ among felines from various geographical locations [1, 19, 20, 21, 22]. Additionally, the absence of a control group makes it difficult to determine whether the observed improvements were due to the dietary change or other unrelated factors in this self‐resolving feline condition. Furthermore, the study was retrospective and lacked microbiota analysis of the patients' feces. Larger, prospective, controlled studies with clinical data and microbiota analysis are needed to validate these findings and clarify the role of the gut‐brain axis in HS pathogenesis.

In conclusion, the improvement in ocular and GI signs following dietary management with a prebiotic‐enriched gastrointestinal diet suggests that this approach may be beneficial for cats with HS, potentially by addressing underlying GI microbiota dysbiosis. However, in refractory cases or when GI symptoms are not fully resolved, additional therapeutic strategies such as probiotic supplementation or fecal transplantation may be required to restore gut homeostasis and achieve complete clinical remission. While the GI diet appeared to facilitate clinical recovery, further controlled studies are needed to validate these findings, establish a causal relationship, and better understand the role of gut‐brain axis modulation in the management of HS in cats.

Disclosure

Artificial intelligence statement: The authors have not used AI to generate any part of the manuscript.

Ethics Statement

This retrospective study reviewed cases of client‐owned cats treated with standard‐of‐care diagnostics and therapy. No experimental procedures were performed, and ethical approval was not required.

Consent

Owner consent was obtained in accordance with institutional and GERVO guidelines.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.