hormones, neuropeptides, and receptors. Many of these substances are involved in neurogenic inflammation, pruritus, and pain sensation, and stress can alter their release. A substantial number of chronic dermatoses in humans are heavily influenced by stress. It has been estimated that in as many as one‐third of the humans with skin disease, the condition is complicated by significant psychosocial and psychiatric morbidity. Patients with atopic skin disorders also have a higher prevalence of anxiety, depression, excitability, and suicidal ideation and a decreased ability to cope with stress.
While many of these emotions may be impossible to confirm in our non‐verbal patients, it is logical to assume that stress has the potential to cause similar pathophysiologic responses that perpetuate the itch‐scratch cycle. Cases of dogs with pyoderma and pruritic skin disease associated with psychogenic factors have been reported (Nagata et al. 2002; Nagata and Shibata 2004). Newer research supports the likelihood that chronic skin disease, especially that which causes pruritis, can lead to stress and subsequent behavior change (Harvey et al. 2019; Yeom et al. 2020; McAuliffe et al. accepted for publication). Harvey et al. (2019) found that dogs with chronic atopic dermatitis demonstrated problematic behaviors such as mounting, chewing, hyperactivity, coprophagia, begging for and stealing food, attention seeking, excitability, excessive grooming, and reduced trainability. The frequency of unwanted behaviors increased when the degree of pruritis was more severe. In another study (data not yet published), dogs with higher levels of pruritis were found to have significantly higher levels of aggression, fear, separation‐related problems, attention‐seeking behaviors, excitability, and sensitivity to touch (McAuliffe et al. accepted for publication). While the exact relationship between these problem behaviors and atopy have not yet been determined, chronic atopy and pruritis is known to result in reduced quality of life; therefore, the potential for chronic anxiety and stress is clear. For that reason, the clinician should remain aware of two important things. First, many skin conditions may be exacerbated in the stressed shelter animal. Second, animals with chronic skin conditions may be more likely to exhibit problem behaviors—and these behaviors might be reduced by treatment that improves their skin condition.
4.6.5.1 Overgrooming
When placed in situations of frustration or conflict, some animals will show displacement behaviors, and grooming is commonly seen as a displacement behavior in many species. Psychogenic alopecia is a term often used to refer to a skin condition of cats in which irregular patches of hair are removed, presumably by licking and chewing. Some have suggested that oriental cat breeds (Siamese, Burmese, Abyssinian) may be at higher risk of developing this problem (Sawyer et al. 1999). Hair may be missing over the flanks, abdomen, front legs, or virtually anywhere on the body. This condition may occur secondary to anxiety or environmental stress but is a diagnosis of exclusion because many pathophysiological conditions can contribute to feline overgrooming. One case series that examined cats with a presumptive diagnosis of psychogenic alopecia found that 76% of the cats had medical conditions causing pruritus (Waisglass et al. 2006). A painful sensation may cause cats to overgroom as well, so radiographs may be helpful in some cases. Regrowth of hair and resolution of the overgrooming, after treatment with pain medication, is suggestive of pain as an underlying cause for the behavior.
While less common, dogs can also overgroom areas of their body due to environmental stress or anxiety, although, as is the case with cats, painful sensations may also lead to overgrooming in the dog. When overgrooming behavior occurs primarily as a response to anxiety or conflict, it has the potential to develop into a repetitive disorder, generalize, and eventually occur even in the absence of the original stressors. Some have referred to this as a compulsive disorder. Regardless of the terminology applied, if the animal is believed to be overgrooming due to stress or anxiety, the primary treatment approach must be aimed at relieving the anxiety through a combination of environmental management, behavioral modification, and anxiety‐relieving medications.
4.6.5.2 Acral Lick Dermatitis
Acral lick dermatitis (ALD), also sometimes referred to as acral lick granuloma, is primarily a dermatological syndrome that is a result of self‐trauma. While some individuals may begin licking a leg to excess due to anxiety, frustration, or conflict, studies have found that many other underlying causes for these lesions are possible (Denerolle et al. 2007). Pruritus due to allergies, orthopedic pain, trauma, neoplasia, bacterial pyoderma, and fungal infections are just a few possibilities.
Once a dog begins to lick and causes an open lesion, the dog will continue to lick it, no matter the original cause. When presented with a patient with ALD, a complete medical workup aimed at identifying the underlying cause is ideal. Long‐term treatment with appropriate antibiotics will almost always be required. Treatment may also include ancillary medications to break the itch‐scratch cycle (e.g., glucocorticoids, antihistamines). Physically preventing the dog from licking the lesion may be necessary to ensure resolution. This may be accomplished with the use of e‐collars, bandages, socks, body suits, or leggings, depending on what the individual patient tolerates.
Once the lesion is completely healed, attention will need to be paid to the patient to determine if they continue to lick at the legs. In the experience of these authors, ALD is rarely a primary behavioral problem. If that is suspected, then the patient needs to be fully evaluated for other signs of fears or anxieties, such as noise sensitivities or phobias, barrier frustration, or separation anxiety, as it is unlikely that ALD would exist as a primary behavioral problem without one of these comorbid conditions. Grooming is a common displacement behavior, and the dog who is anxious about the strange sights, sounds, and smells of the shelter, as well as the sudden change in its living arrangement and separation from familiar people, may be inclined to exhibit displacement grooming to the extent that it develops or worsens an existing ALD.
4.6.5.3 Feline Hyperesthesia
Feline hyperesthesia is a poorly understood syndrome, known by a variety of different names, including rolling skin syndrome, twitchy skin syndrome, and feline neurodermatitis, to name a few. It is characterized by short episodes of thoracolumbar skin rolling or rippling, and, in some cases, epaxial muscle spasms. Cats may appear anxious or agitated and demonstrate exaggerated tail movements, running, vocalizations, or self‐directed aggression. The self‐directed aggression may be the extreme end of a spectrum that includes excessive licking, plucking, biting, and/or chewing directed at the tail, lumbar, flank, or anal area. In some cases, the increased motor activity, exaggerated rolling, crouching, and elevation of the perineal area may be confused with the behavior typically shown by an estrus female.
Feline hyperesthesia is referred to as idiopathic in most textbooks because no single causal factor has been elucidated. It has been hypothesized that the behaviors are a result of focal seizures, sensory neuropathies, and dermatologic disease resulting in pruritus. As is the case with other skin conditions, it is likely that environmental and social stressors play a role in this condition. Systemic diseases such as toxoplasmosis and hyperthyroidism should be ruled out, as well as painful spinal or skin conditions, severe pruritus, FLUTD, anal sacculitis, and myositis, as they may all contribute to the behavior. Any disease condition that affects the central nervous system or alters reactivity to stimuli will need to be ruled out if the clinician is presented with a cat showing signs similar to feline hyperesthesia (Ciribassi 2009).
After ruling out and treating any underlying medical problems causing pain or pruritus, feline hyperesthesia may be treated empirically as a partial seizure disorder. Both phenobarbital and primidone have been used to treat the condition (Aronson 1998), as well as clomipramine and fluoxetine (Overall 1998). Ultimately, treatment of every individual animal will need to reflect the putative etiological basis of that particular case. Attention will need to be paid to identifying and, if possible, removing the environmental stressors that may be contributing to the problem.
4.6.5.4
