House soiling in cats

House soiling – an introduction

Cats have long been assumed to be an independent species requiring minimal care – but this assumption can often result in deficiencies in their environment and a failure to meet a cat’s basic needs. As a result, the cat’s health, a triad comprised of physical, emotional, and cognitive wellbeing (Figure 1) is likely to be negatively impacted. Caregivers have nearly complete control over their cat’s life, making decisions about diet, feeding schedules, other cats and other pets, toys, resting spaces and litter boxes. In spite of having minimal or no control, as long as the cat is able to, they will remain cooperative with human expectations. However, when deficiencies in the environment exist and the health triad is disturbed, their ability to conform diminishes. For litter box use, this can mean that alternative latrining locations become the appropriate place for the cat to void urine and/or defecate. House soiling is therefore the act of depositing urine or feces outside of a toileting area that the caregiver has designated as acceptable (Box 1). 

Box 1. House soiling terminology.

House soiling – changing the perspective and language

Some of the terminology used in reference to house soiling can have a misleading impact on the perceived cause(s), and specifically on the cat’s behavior and intentions. For example, the word “inappropriate” (urination, defecation, latrining) is often used, but it is erroneous to consider the behavior as being inappropriate, and erroneous to consider that the cat is aware of this and acting with malicious intent. Lacking self-reflection and internal dialogue, cats do not avoid the litter box for revenge or other vindictive reasons 1. When they defecate or urinate, they are making the decision to do so in a location that is appropriate to them at the time and for their needs, much as they would out of doors. By applying the correct language and avoiding terms like “inappropriate”, we can correctly direct caregivers away from the concept of misbehavior and turn the focus to what the cat’s essential needs are, with the goal of resolving the problem. Of equal or greater importance is that by educating all caregivers about the cat’s essential needs before problems occur, we can actively prevent house-soiling issues from ever arising.

Causes of house soiling

House soiling is a multifactorial problem that signals there are derangements in the cat’s physical, emotional or cognitive wellbeing. The main medical differential diagnoses for feline urine house soiling include lower urinary tract disease (FLUTD), constipation, dehydration, neurologic disease and/or neoplasia. FLUTD describes a group of diseases of the lower urinary tract which may have overlapping clinical signs and are not necessarily mutually exclusive. These include feline idiopathic cystitis (FIC), urolithiasis, crystalluria, infection and/or bladder neoplasia. The main medical differential diagnoses for house soiling with feces include structural abnormalities, constipation, neurologic conditions, urinary tract disease, intestinal disease, dehydration and/or neoplasia. Additionally, any condition that causes pain may contribute to inconsistent litter box use and aversion. Deficiencies in the environmental needs of the cat that can lead to house soiling include insufficient availability, or incorrect distribution or management of resources such as litter boxes, feeding and/or water stations, scratching surfaces, and sleeping locations. Inter-cat issues may also lead to litter box avoidance. Cats in multi-cat households may have reduced access if insufficient boxes are available, or if a cat is blocking access. Intact males or males neutered after the onset of puberty, and even some neutered males and females, may engage in house soiling in the form of territorial urine marking (spraying) or marking with feces (middening). A presumed territorial nature for certain types of house soiling does not rule out the need for a full medical evaluation 2.

Barriers to identification and resolution

Caregivers may not be aware that their cat is house soiling, or only become aware of the problem after it has been going on for a long period. They may draw mistaken conclusions about the cause(s), attempting to resolve the concern on their own. They may also fail to report the problem, either because they are unaware of the potential for sickness and pain associated with house soiling, or due to an unwillingness to pursue what they misconceive to be a potentially expensive and doomed process. In a 2016 telephone survey conducted of 281 households owning 455 cats, 26% of all cats in the study were reported to have urinated or defecated outside the litter box at some point in their lives 3, but only 31.7% of these cats were evaluated by a veterinarian for this condition. For 56.7% of cats the behavior resolved, but for the remainder the behavior persisted. This supports the experience in clinical practice, whereby caregivers allow house soiling to continue, making little to no consistent effort to determine a path to resolution, sometimes for months or years. It may sometimes be mentioned in passing at a preventive care visit, and at times caregivers may dismiss house soiling as “revengeful” behavior. Litter box use and urination and defecation should be included as part of every history taking. Close-ended questions with “yes” or “no” answers do not give the caregiver the appropriate opportunity to evaluate and report accurately on their cat’s activities. Open-ended questions will increase information disclosure by providing some degree of acceptability to the activity we are asking about and allowing the caregiver to frame the information in their own words. For example, a close-ended question such as “Does your cat use the litter box?” should be replaced with “How often does your cat urinate or defecate outside the litter box?” or “Where does your cat urinate or defecate outside the litter box?” For the cat that intermittently soils outside the litter box, the answer to the closed question is likely to be “yes”, but the answers to the open-ended questions are likely to be much more revealing.

Getting a good history

When it has been determined that a cat is house soiling, signalment and a detailed history of the problem require special consideration (Box 2). Signalment may suggest or eliminate certain differential diagnoses – for example, neutered male cats are at increased risk of FLUTD. The history information should include diet (brand, canned or dry, treats), appetite (actual intake amounts), perceived weight loss or gain, water intake, and characteristics of the cat’s urine and feces. A healthy adult cat urinates approximately 30 to 40 mL/kg per day, although large variations exist depending on diet, water consumption and health status. Caregivers should be asked about changes in urine clump diameter or size and encouraged to have increased awareness of urine volumes for each cat in the household. This can be easier to track than it might be assumed, particularly if specific cats have preferred litter boxes that they use, and it may be possible to set up cameras to gather more information. Defecation is typically once or twice daily, although a less frequent but regular pattern (ex. q48hrs) may be observed in some cats. Fecal characteristics including consistency should be evaluated using a specific fecal score chart which will provide significant detail about the stool, even if the caregiver believes it to be “normal”. The clinician should collect information on the duration of the problem, other behavior changes, when and where the problem is occurring, under what apparent circumstances, litter box care, and under what conditions the cat uses the litter box (if at all). A census of other pets in the home should include an evaluation of inter-pet relationships, particularly in multi-cat households, as this is a known risk factor for house soiling 4.

Box 2. Important historical information for assessing house soiling in cats.

Assessment of physical wellbeing

A thorough physical examination is critical to identifying physical changes secondary to illness or which predispose to litter box issues. For example, obese cats may have mobility issues, but may also be diabetic, which causes polyuria and predisposes to lower urinary infection, all potential causes of house soiling. All affected cats require a basic urinalysis (including macroscopic assessment, specific gravity, biochemistry analysis, and sediment microscopy). This includes cases with fecal house soiling, as some of these patients may have painful urination, leading them to defecate away from the pain-associated litter box. Cystocentesis is the gold standard for urine collection, reducing the risk of false positive sediment or culture results 5, with samples ideally assessed immediately to reduce the risk of struvite formation in a stored sample, which can result in a false diagnosis of crystalluria 6. Urine culture and sensitivity should be carried out for any cat with an active sediment (white blood cells, bacteria), low urine specific gravity (USG) and/or glucosuria 5. Hematuria in the absence of any other changes may be iatrogenic, but is also characteristic of cats with FLUTD, particularly those experiencing an episode of FIC 7,8. It may be possible to monitor for microscopic hematuria at home by using a commercial litter additive product that is highly sensitive for detection of blood. Another important part of the minimum database required to rule out systemic disease is blood testing, especially in cats that are middle age (7-10 years) and older 9. Relevant tests include clinical chemistry panels, electrolytes, total T₄, a complete blood count and retroviral testing. Blood pressure assessments will also be critical in cats over 8 years of age, as hypertension can cause behavioral changes including house soiling. Other investigations include imaging of the abdomen by plain or contrast radiography, ultrasound, or other modalities 10,11.

The environmental impact on feline health

The 5 essential pillars of a healthy feline environment

Given that house soiling is a multifactorial issue, it is critical that medical concerns be identified and addressed, but it is equally important to evaluate the cat’s environment. Cats are a unique species, being obligate carnivores that are predator but also prey, so they need a territory in which they can hunt safely, and which provides them with their essential resources with minimal threat of predation or competition. Their overall needs are described in the five pillars of a healthy feline environment (Figure 2) 12. Deficiencies in one or more pillars can predispose to disturbances in the health triad, potentially leading to issues such as house soiling. When evaluating the cat’s home environment, it is ideal to provide the caregiver with detailed information about these five pillars, and work with them to evaluate what deficiencies might exist. Adjustments to the environment and resource management can then be considered. Caregivers can also be encouraged to monitor the cat’s environment for disruptions in the five pillars in the future, which can facilitate prompt corrections, avoiding further issues.

Pillar 1. Provide a safe place

Cats need to feel safe within their own home territory, with the sense of safety from their own perspective, not that of the caregiver (as many people assume that their cat is and should feel safe within their home). They may not be aware of potential outdoor threats and might erroneously expect the cat to understand that those threats cannot enter the home. For example, neighboring outdoor cats may not have access to the home, but their sight, sound and/or smell can lead the indoor cat to perceive a threat to its own safety and resources. Within the home, there may also be smells, noises, or other animals or humans that make the cat feel unsafe. Since caregivers do not have complete control over this at all times, spaces are needed throughout the home where the cat can hide and thus increase its perceived safety (Figure 3).

Pillar 2. Provide multiple and separated key environmental resources

Within the cat’s territory, key environmental resources include separated food and water sources; appropriately managed litter trays; resting places at different vertical heights with some that only fit one individual cat (Figure 4); and multiple scratching resources. As solo hunters, it is recommended that cats be fed singly in separate rooms, or with visual barriers between them and a minimum of 6 feet/2 meters apart 13. While definitive research is lacking, feline experts recommend that water bowls be placed away from feeding stations, as the cat’s natural preference is to keep food away from water sources. All resources should be provided in multiples and distributed to various areas throughout the home; this allows the cat the option to choose a resource in a particular location if another location does not feel safe or cannot be easily accessed at that moment. For example, if another cat is blocking access to a specific litter box, a second litter box in a different location may prevent a house-soiling event. 

Pillar 3. Provide opportunities for play and predatory behavior

The cat’s natural hunting instincts require an outlet, even in an indoor setting where food is available. Puzzle feeders can promote predatory behavior and maintain mental acuity. Interactive play with caregivers for short periods once or more each day will also help to fulfill the cat’s predatory drive. Caregivers may need to try multiple different puzzle feeders and toy styles to determine what their cat prefers, switching these as the cat’s preferences change. Play and predatory behavior enhance physical fitness and mental acuity.

Pillar 4. Provide positive, consistent & predictable human-cat social interaction

Cats are naturally solitary by nature, and while they engage socially with humans, they prefer to interact on their own terms and at their own initiation. As a social species, humans would prefer more physical interactions with their cat, and may want to do so spontaneously and at times that do not fit with the cat’s desires. Further, not all humans understand how to interact respectfully with cats. A person may be physical in a way that cats do not like, such as rubbing or petting them vigorously and/or on parts of their body they don’t want touched; holding them against their will; or picking the cat up when they don’t wish to be. “Hand play” is also problematic for cats, potentially leading to injury (bites, scratches etc.) and other repulsive behaviors; this is not play and will increase the cat’s anxiety. Human social interactions which cause the cat to experience fear or anxiety will increase the likelihood of unwanted behaviors, including house soiling.

Pillar 5. Provide an environment that respects the cat’s sense of smell

Cats have a sense of smell that is significantly more heightened than that of humans. The many fragrances and scents that humans like in their homes, including scented cat litter, can reduce the cat’s ability to survey the territory for predators, potentially making them feel unsafe. These smells are also potentially irritating to the cat’s senses. 

Litter boxes require special attention 

Litter boxes are a critical Pillar 2 key resource that require particular attention when assessing house-soiling cases. Cats are expected to urinate and defecate within prescribed containers which typically contain a substrate that is hopefully conducive to digging a hole and burying of feces or urine. The humans living with the cat(s) make decisions about how many of these containers there will be, how many cats there will be to share them with, how large or small they will be, where they will be located, what they will contain and how often they will be cleaned out. Out of doors, domestic cats make all of these decisions based on their own needs including a sense of safety, their preferences, and the defining borders of their home territory. While cats usually accept what is available, a house-soiling cat has likely developed some aversion or objection to the litter box that may be related to the box itself. During the initial house-soiling consult, it is helpful to provide caregivers with a list of cats’ preferred litter box criteria (Box 3). Caregivers may indicate that their cat has never had any concerns with the litter box situation, but it is important to emphasize that acceptance of certain litter standards depends on good physical, emotional and cognitive wellbeing. Where there is reduced health, it is unlikely that the cat will be as willing or able to tolerate litter boxes that fail to meet these criteria. House soiling will sometimes reduce in frequency or stop altogether once litter box criteria have been met.

Box 3. Litter box criteria.

Inter-cat relationships

It is frequently assumed that cats need another feline companion in the home, and will be lonely without one; however, the inherent solitary nature of the cat means that in most situations they prefer not to share their territory or resources. This is not to say that cats cannot form positive relationships with other cats in the home, but being solitary is a cat’s preferred default social behavior. Cats may develop social attachments to other cats in the household and become friends – but more often they become foes, existing in the same household with the other cat either in apparent indifference or with repeated inter-cat tensions (Box 4). These tensions often go unnoticed by the caregiver, yet these can be a major cause of stress and subsequent house soiling in the multi-cat household. The ability of caregivers to recognize whether cats are friends or foes is very limited, due to their lack of understanding of the five pillars, cat body language and cat interactions. Cohabitating cats that are friends will express affiliative behaviors including allogrooming (grooming one another), co-sleeping (in physical contact or close proximity), and other physically interactive behaviors such as nose touching, tail wrapping, facial or body rubbing and play. Foes rarely or never express affiliative behaviors, but rather will avoid one another to minimize conflict and possibly express agonistic behaviors. Foes may time-share resources, or one cat may block access to resources, and the cats may exchange vocal repulsive messages (hissing or growling) and fight. Discerning the difference between play and fighting is also difficult in some instances 14, making the identification of friend or foe more challenging. Cats that are playing will take turns initiating the activity, with rest periods throughout, and there is little to no growling or hissing. Fighting can look like play at times, as cats engage in wrestling and chasing, but these activities are often initiated by the same cat, sometimes with stalking behavior; in addition, rest periods are not taken, there is frequent growling and hissing, and physical fighting will ensue. Foe-related behaviors do not stem from a dominance hierarchy, which is not part of the cat’s social structures 15, but rather from the need to protect the territory and resources, which appear limited. To meet the needs of each cat within the house, each individual must have free access to its own key resources, ideally positioned out of sight of the other cats. This provides cats the opportunity to develop their own territory within the home, avoiding others as much as they choose to.

Box 4. Friend or foe? Indicators for a friend or foe relationship.

Management & resolution of house-soiling behaviors

As a multifactorial problem, treatment of house soiling is best approached from a holistic perspective. This means addressing the physical, emotional, and cognitive well-being of the cat, rather than focusing on one dimensional solution. Issues between cats in multi-cat households can often be addressed by examining deficiencies in the five pillars, including meeting all litter box criteria if possible, whilst cats diagnosed with specific medical conditions will require targeted therapy in addition to environmental adjustments. 

Dietary modifications

A change in diet can be helpful in the long-term management of cats with house-soiling issues. Prescription diets targeted to specific medical conditions are important, but a change in formulation (e.g., dry to canned) may be recommended. For example, cats with FLUTD will not only benefit from a targeted therapeutic diet, but they will also benefit from a transition to a wet food as a means of promoting a more dilute urine. Overweight cats that develop litter box issues should be started on a progressive weight loss program. Where cases of house soiling include increased anxiety, or a decreased ability to handle stressors, such as for cats with FIC, foods containing calming supplements can be incorporated into the treatment plan 16, but these must be the cat’s sole source of nutrition and used consistently in the long term. Nutraceutical products which assist in reduction of anxiety or alter inflammation are of potential benefit; products which contain L-theanine, alpha-S1 tryptic casein, milk hydrolysate alpha-casozepine, whey protein and/or omega-3 fatty acids (OFA-3) are all available commercially for cats 17.

Pharmacologic interventions

Analgesics are often overlooked in cases of house soiling, yet pain can play a direct role in litter box avoidance for numerous reasons. For example, mature cats are at increased risk of degenerative joint disease (DJD) 18 which can decrease mobility, reduce ease of access to litter boxes, and predispose to house soiling. Analgesia should be a major component of most therapeutic plans for cats with house soiling whenever clinical illness has been diagnosed.

A variety of behavioral modification drugs have been used empirically in cats with house soiling concerns, but their efficacy will vary with each situation. Treatment of house soiling will be most successful when an accurate diagnosis is made and patient needs are addressed, and all medical, dietary, environmental and resource concerns must be addressed prior to or in conjunction with the use of pharmacologic agents. Anxiety issues will improve with environmental adjustments 19, but in some cases anxiolytic or anti-anxiety medications (selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs) etc.) or other behavioral modifying pharmacologic drugs may be needed (Box 5). Caregivers will need to understand that these latter medications may take days or weeks to take effect and that they will not work without other management strategies. Behavioral modification pharmacologic drugs should be used as a last resort, and should be considered as one component of the holistic approach, with the intention of being able to discontinue medications over time. Selection of drugs will be based on the identified areas of concern, whether these are anxiety based, or secondary to inter-cat issues in a multi-cat household. 

Box 5. Psychotropic medications which may be needed to supplement other treatment approaches for house soiling). Drug interventions will not work in the absence of other management strategies and should be used as a last resort, with the intention of discontinuing their use over time. Drug selection will be based on the individual patient and washout periods between drugs may be required (e.g., transitioning from a TCA or SSRI to an MAOI requires a 5-week washout. Note TCA or SSRIs should never be used with MAOI-B (from 20).

Conclusion

Resolution of house soiling issues requires a dedicated team approach including caregiver and the veterinary staff. Caregivers need to be made aware of the multifactorial nature of the issue from the outset, which will facilitate development of a treatment plan that can be successful over time and avoid the misconception that the problem is a “one and done” matter. There are rarely simple solutions, but the sooner an issue is identified, the clearer the pathway to resolution will be. At times house soiling may have been occurring for an extended period, and this may increase the challenges associated with untangling the problem; the veterinary team must commit to providing caregivers with ongoing assistance throughout the process, promoting good communication at all times.