Inhalant allergy (atopy) is the second most common cause of skin itchiness in dogs. It can be difficult to eliminate, because the allergens are in the air we breathe. Atopy is a complicating and/or primary factor in many skin disorders. It responds to antihistamines and corticosteroids. Allergy testing and desensitization serum injections are recommended to reduce the need for oral medications which may have side effects.

Sarcoptic mange (scabies) is a microscopic mite that burrows under the skin causing severe itchiness. It can be hard to detect on skin samples under the microscope; however, it makes its presence well known. Often, it is treated as a rule out cause for itching before pursuing other diagnostics. Dips and extra-label use of injectable de-wormers are used to kill scabies mites.

Ringworm isn’t a worm at all. It is a fungal infection of the skin. It causes the hairs to break off and leaves a scaly red patch on the skin that may itch. Mild cases may respond to topical anti-fungal ointments; whereas, generalized infection requires the use of oral antifungal drugs concurrently with medicated shampoos or dips.

Yeast (Malassezia) infections of the skin are notoriously itchy. They also exude an offensive musty odor from the skin. Hyperpigmented and thickened skin (elephant skin) is a common appearance for dogs with Malassezia infections. They require the use of anti-fungal drugs and shampoos, and are almost always secondary to an underlying hormone disorder or primary allergic dermatitis.
Diseases that cause the skin to be especially susceptible to pruritus are Hypothyroidism and Cushing’s disease. These hormone-related illnesses cause the skin to be prone to bacterial and yeast infections. Hypothyroidism is a condition where the thyroid gland does not produce enough thyroxine or T4. T4 is important in cellular function in all parts of the body. In Cushing’s disease, the adrenal gland over-produces cortisol (cortisone). This causes the skin’s immune defenses to stop responding to intruders like bacteria, mites, and yeast.

Food allergies are another potential cause for pruritus. The itching usually occurs primarily around the eyes, chin, and ears. The dog may also lick its feet. Recurrent ear infections are common in dogs with untreated food allergies. Hypoallergenic feeding trials are the method of diagnosing as well as treating allergies to certain food ingredients.

An Elizabethan collar can be used to prevent self trauma and the consequences thereof, but the underlying cause must be addressed to provide the dog relief from the urge to scratch.

It is always important to have skin problems checked out by the veterinarian sooner than later. While the primary cause of itching may be relatively straight forward to diagnose and treat, deep-seated secondary infection can be difficult, expensive, and time-consuming to resolve.