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

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 of Pet Itchiness

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 for Itchiness in Cats & Dogs

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 for Itchiness in Pets

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