A self-directed behavior is any behavior that an animal directs toward itself repeatedly and consistently in the absence of a primary medical cause. Self-directed behaviors can include a range of activities from excessive maintenance behaviors, such as grooming, to redirected aggression that may or may not be purposeful. Although the prevalence of self-directed behaviors is not well-documented in dogs or cats, it is likely underappreciated because animals are not typically presented for evaluation of such behaviors unless the clients think their pets are manifesting a behavior problem or some degree of injury as a consequence of the behavior.

Self-directed behaviors that result in any degree of self-mutilation or damage are classified as self-injurious behaviors.^1,2 Because these behaviors may occur reclusively, an animal may be presented for evaluation of lesions that appear to have developed spontaneously. To identify self-injurious behavior, look for barbering or removal of hair, abrasion, petechiation, or ulcers on any body part resulting from the animal's using its teeth, tongue, claws, or an external substrate (e.g. rubbing against a wall) repeatedly and consistently in the absence of a primary dermatologic or physiologic condition.^1,2 Self-injurious behavior is not a clinical diagnosis but an assessment that an animal's condition is the result of a primary behavioral etiology.

Self-injurious behavior may lead to behavioral dermatoses, dermatologic conditions for which a substantive behavioral or emotional component is present.¹ In humans, emotional factors affect the management of at least one-third of patients with dermatologic conditions.^3,4 For example, chronic dermatoses such as acne, rosacea, and seborrheic dermatitis may be exacerbated by emotional stress. Furthermore, pruritus and pain associated with primary dermatoses may substantially affect emotional reactivity, making an individual more reactive to potentially stressful situations.¹ Based on underlying psychoneuroendocrinologic mechanisms common to both humans and animals, it is reasonable to assume that behavioral or emotional factors may contribute to a similar percentage of behavioral dermatoses in companion animals.

When evaluating animals for self-directed behaviors, it is important to determine whether the behavior falls within the species' normal behavioral repertoire. For example, self-grooming is a normal maintenance behavior that facilitates cleansing, parasite removal, and thermoregulation. Normal grooming behaviors include licking the hair and skin, nibbling, biting, scratching, rolling, and rubbing the face with the forepaws or environmental substrates.

Although normal grooming behaviors are well-recognized, how frequently and for what amount of time healthy household dogs or cats typically engage in such behaviors are not well-documented. Because environmental and social stimuli may affect grooming behaviors, it is likely that the normal range for daily grooming time varies with an animal's living conditions. One study of farm cats reported that grooming occupied 15% of the cats' time.⁵ Another study of confined indoor cats reported that oral grooming made up 4% of the cats' time (8% of nonsleeping or nonresting time), and grooming by scratching took up ¹/50th of the time used for oral grooming.⁶ Thus, determining what constitutes excessive grooming often depends on an observed predominance of grooming behavior or physical manifestations of injury secondary to grooming.