Itchiness in Dogs & Cats

Itchiness in Dogs & Cats – An Overview

  • “Pruritus” is the medical term for itching or itchiness; it is the itching sensation that provokes the desire to scratch, rub, chew or lick
  • Pruritus is an indicator of inflamed skin
  • The term is not a diagnosis but rather is a description of a clinical sign

Species

  • Dogs
  • Cats

Signs/Observed Changes in the Pet

  • Scratching
  • Licking
  • Biting
  • Rubbing
  • Chewing
  • Self-trauma
  • Inflammation of the skin (known as “dermatitis”)
  • Hair loss (known as “alopecia”); hair loss without inflammation may be the only sign in some cats
  • Other signs determined by underlying cause

Causes

  • Parasites—fleas; mites (canine scabies [Sarcoptes], Demodex, ear mites [Otodectes], feline scabies [Notoedres], “walking dandruff” [Cheyletiella], harvest mite or red bud [Trombicula]); lice; rhabditic dermatitis (Pelodera strongyloides); or migration of internal parasites
  • Allergies—parasite allergy; atopy (disease in which the pet is sensitized [or “allergic”] to substances found in the environment [such as pollen] that normally would not cause any health problems); food allergy; contact allergy; drug allergy; allergy to skin bacteria (known as “bacterial hypersensitivity”); allergy to Malassezia (a yeast found on the skin)
  • Bacterial or fungal infections—Staphylococcus (a bacteria) and Malassezia pachydermatis (a yeast or fungus); rarely a dermatophyte (fungus living on the skin, hair, or nails); however, Trichophyton is a dermatophyte that tends to cause more itchy skin disease than the other dermatophytes
  • Miscellaneous—excessive scaling of the skin (known as “seborrhea”); calcium deposits in the skin (known as “calcinosis cutis”); skin tumors or cancer
  • Immune-mediated skin diseases and hormonal skin diseases can be variably itchy
  • Psychological skin diseases may be associated with itchiness

Risk Factors

  • Exposure to other animals with parasites

Treatment

Health Care

  • More than one disease can contribute to itching
  • The use of mechanical restraint (such as an Elizabeth collar) can be a helpful option, but is seldom feasible in long-term treatment
  • Treat for secondary infections, which are common

Diet

  • Depends on underlying cause
  • Usually no change in diet needed, unless suspected food allergey

Medication

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive

Medications Applied to the Skin Directly (Known as “Topical Therapy”)

  • Topical therapy is helpful in mildly itchy pets
  • For localized areas of itchiness or skin inflammation, sprays, lotions and creams are most appropriate
  • If the itching involves many areas or widespread areas, shampoos are the preferred means of application
  • Antibacterial shampoos help control bacterial infections that cause itching; however, some antibacterial shampoos (such as those containing benzoyl peroxide or iodine) can cause increased itching
  • Colloidal oatmeal is common in all forms of topical therapy; its duration of effect usually is less than two days
  • Topical antihistamines may be found alone or in combination with other ingredients; they may not have a beneficial effect
  • Topical anesthetics may offer only a very short duration of effect
  • Antimicrobial shampoos help control bacterial infections that cause itching; however, some contain ingredients (such as benzoyl peroxide or iodine) that can increase itchiness through excessive drying
  • Lime sulfur (which has a bad odor and can stain) can decrease itching, while also having anti-parasitic, antibacterial, and antifungal properties
  • Topical steroids probably are the most useful topical medications; hydrocortisone is the mildest and most common topical steroid; stronger steroids (such as betamethasone) may be more effective and are more expensive; a triamcinolone-containing prescription spray (Genesis® Topical Spray, Virbac) is effective in decreasing itchiness (pruritus)
  • Some topical steroid medications also contain ingredients (such as alcohol), which can aggravate already irritated skin
  • In some pets, the application of any substance, including water (especially warm water), can result in an increased level of itchiness; however, cool water often is soothing

Medications Administered by Mouth or by Injection (Systemic Therapy)

  • Steroids to decrease inflammation and itchiness of the skin
  • Cyclosporine to decrease the immune response
  • For pets affected with airborne allergies for more than a few months out of the year, “allergy shots” (known as “allergen specific immunotherapy”) are appropriate, frequently beneficial, and may lead to a cure (in some cases)
  • Antihistamines (such as hydroxyzine, diphenhydramine, and chlorpheniramine) to prevent inflammation and itching
  • Fatty acids are available in powders, liquids, and capsules; they help block pathways that lead to inflammation, but may require 6–8 weeks of use until maximum effect is observed; fatty acids work better as preventive medications, rather than stopping the inflammation once it has become a problem; they also help reduce dry or flaky skin, which can cause itching
  • Medications to relieve anxiety or depression (known as “psychogenic drugs”) can be helpful in controlling itchiness; include such drugs as amitriptyline, fluoxetine, and diazepam
  • In rare cases, alternative medications to decrease the immune response (known as “immunosuppressive drugs,” such as azathioprine) may be utilized; however, they should be reserved for instances when all other treatments have failed

Follow-Up Care

Patient Monitoring

  • Patient monitoring is imperative; pets should be examined periodically to evaluate response to treatment
  • Pets receiving long-term (chronic) medications should be evaluated every 3–12 months for potential side effects as well as occurrence of new contributing factors

Preventions and Avoidance

  • Prevent infestation with parasites (such as fleas and mites)
  • Avoid foods identified as causing food allergy for your pet

Possible Complications

  • Owner frustration is common
  • Complications (such as increased thirst [known as “polydipsia”] and increased urination [known as “polyuria”]) are common with long-term (chronic) steroid use

Expected Course and Prognosis

  • Depend on underlying cause
  • Many causes of itchiness in pets are extremely frustrating to control

Key Points

  • Many different unrelated diseases may contribute to itchiness (pruritus), and control of one disease does not mean that other causes cannot be contributing to itchiness or cannot occur later
  • Multiple causes (such as flea allergy, inhalant allergy, and bacterial skin infection [known as “pyoderma”]) commonly are present in a single patient
  • Elimination of bacterial skin infection (pyoderma) and flea-associated disease may not be enough to significantly reduce itchiness
  • Food-allergy and inhalant-allergic pets may do well during the winter season with a hypoallergenic diet, only to become itchy during the warmer months in association with inhalant allergies

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