Animal Allergy & Dermatology Center of Central TX

2207 Lake Austin Boulevard
Austin, TX 78703


Skin Diseases and Conditions

There are many skin diseases/conditions which afflict pets. As they often mimic each other in their presentation of symptoms, evaluation and treatment by a veterinarian with special training in this area is crucially important. Dr. Nichols possesses the experience necessary to properly determine which disease is afflicting your pet and has the advanced education to direct proper treatment. Below are brief descriptions of some of the most common skin issues of dogs and cats -

Pyoderma is a bacterial skin infection (bacterial dermatitis) usually caused by Staphylococcus bacteria. These bacteria do not cause disease on normal skin; however, underlying conditions such as allergies can cause changes in the skin which make it more susceptible to infection. Thus, it is important to diagnose and treat the root cause while also treating the pyoderma. Antibacterial shampoos/sprays/rinses and/or oral antibiotics are prescribed to clear the infection. It is important to give the full dose of antibiotics for the entire time prescribed, even if your pet's skin looks better as the naked eye can not discern if an infection has been abolished; evaluation of a sample under a microscope is the only way to determine if the skin is clear of infection. It is very important to have a recheck appointment to assess the infection's response to treatment as a longer course or modification of medications may be required. Stopping the antibiotic too soon may lead to further problems such as resistance to the antibiotic or the need to start treatment again from the beginning. Diagnosis and treatment of the primary problem is the key to preventing recurrence of this secondary condition.

Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Resistant Staphylococcus intermedius (MRSI) are species of Staphylococcal bacteria. This bacteria is normal in low numbers on the skin of people and animals, but have the capacity to overgrow and create infections, especially in people or animals who are immunosuppressed. In some cases, especially after exposure to multiple or subtherapeutic doses of antibiotics, the bacteria can become resistant to multiple antibiotics and thus, resistant staph develops. Resistant staph has the potential to spread from pets to their owners, especially those who are immunosuppressed, the elderly, or young children. Owners of animals with resistant staph infections should wash their hands after touching their pet and not let their pet lick or nuzzle them. Carefully following Dr. Nichols' specific treatment plan of oral antibiotic and topical therapies is extremely important in order to eradicate this bacteria.

Malassezia Dermatitis (Yeast Dermatitis) is a common fungal infection of the skin and ears. Although fungal organisms normally live on the bodies of animals and people without causing issues, an underlying primary problem can cause an overgrowth which leads to secondary infection. Triggers for yeast dermatitis include allergies (environmental, food, flea), skin parasites, hormonal abnormalities, and immunosuppressive conditions. Symptoms include red skin, oily skin and hair, and yellow crusting or scaling. In chronic cases, the skin becomes leathery, thick, and dark. Most animals afflicted are very itchy and often have an unpleasant odor emanating from their skin and/or ears. Owners often notice the odor of a yeast infection resembles the smell of corn chips. Diagnostics include cytology and/or skin scrapes for microscopic analysis. While treating the yeast infection, it is very important to diagnose the underlying cause of the infection and treat that primary problem, otherwise the yeast dermatitis is likely to chronically recur.

Pyotraumatic Dermatitis (referred to as a hot spot) starts when a dog incessantly licks, chews, or scratches an area of the body in response to a painful or itchy sensation. This self-trauma then results in a rapidly developing area of redness, hair loss, and oozing and eroded skin that is often painful and infected with bacteria. Hot spots occur most frequently on the trunk, base of the tail, outer thigh, neck, or face. Potential underlying causes for hot spots include allergies, parasites, or bacterial and/or fungus infections. Appropriate topical and/or oral therapies as well as prevention of continuing trauma (via E collar or t-shirt) are needed to clear up the affected skin. Ultimately, identifying and addressing the underlying cause of the hot spot is needed in order to stop this chronic condition. 

Endocrine Disorders such as Hypothyroidism, Cushing's Disease, Sex Hormone Imbalance, and Growth Hormone Deficiency all cause skin disease. The body contains several glands that secrete hormones into the bloodstream. These glands and their hormones are referred to as the Endocrine System. The hormones secreted are vital to normal skin and hair coat production, and are necessary for the regulation of other body functions. A common cause of skin diseases is failure of an endocrine organ to secrete the proper amount of its hormone. This usually results in some degree of hair loss and abnormal skin quality. Depending on the hormone involved, there may be other subtle changes noted in the pet's medical history or found on physical exam. This information aids Dr. Nichols in directing his diagnostics. Hormone disorders usually carry a good prognosis; however, definitive diagnosis of the Endocrine Disorder is necessary to appropriately direct therapy. 

Acral Lick Granuloma is a commonly seen skin disorder of dogs which results in wounds caused by bacterial or fungal infections, mites, allergies, cancer, joint disease, or previous trauma. In older dogs, sometimes an obsessive-compulsive disorder (stereotypic behavior) due to hypothyroidism plays a role. Because of the underlying condition, dogs lick an area until they cause hair loss and erosion of the superficial skin layers. The consequence is further itching, which in turn results in more licking. This itch-lick cycle is exacerbated by the fact that damaged cells release endorphins. Because Acral Lick Granuloma is difficult to cure, it often comes with a guarded prognosis. Dogs that receive early treatment have a better prospect of recovery.

Canine Solar Dermatitis is a common dermatologic disorder in hot, sunny climates. Solar Dermatitis often mimics other skin diseases such as allergies, pyoderma, or fungal skin disease. Left untreated, irreversible damage or sun-induced skin cancers can develop. Thinly haired areas are most prone to sun damage. The duration and intensity of sun exposure influences the degree of skin damage. Initial signs are scaly lesions which may be tender. With repeated exposure, actinic follicilitis, follicular cyst formation, and dermal fibrosis occur, as well as thickened and scarred skin with comedones, erosions, ulcers, crusts, and draining tracts. Secondary bacterial infections are common. This disorder may also result in tumors, such as squamous cell carcinoma, hemangloma, and cutaneous hemangiosarcoma. Clinical signs, ruling out other causes (such as bacterial, demodex, or dermatophyte infections), and ultimately skin biopsies are used to properly diagnose this condition. 

Eosinophilic Granuloma Complex is rare in dogs, yet common in cats. There are three types of this complex in cats, which present as ulcerated and swollen lesions usually around the lips, in the mouth, or on the abdomen or medial thighs. These lesions may be ulcerated, swollen, raised, and/or red. In dogs, the lesions are commonly on the palate inside the mouth and are raised, red, and ulcerated or are greenish masses on the tongue. Investigation of the underlying cause is essential, and may include treatment for parasites, a hypoallergenic food trial for possible food allergy, and/or intradermal allergy testing for environmental allergies.

Sebaceous adenoma (also known as Nodular Sebaceous Hyperplasia) is a benign tumor of the sebaceous glands of the skin. Although commonly referred to as "warts," these tumors are not true warts as they are not viral-induced. These skin growths are more prevalent in older, small breed dogs. These tumors present as single to multiple raised, hairless skin masses which may ooze an oily white substance. If the tumor becomes traumatized or secondarily infected, the dog may lick or chew at the lesions. After proper diagnosis, treatment is most often not needed unless the lesions grow, change, or bother the dog. If so, they should be removed and biopsied.

Sebaceous adenitis is an inflammatory disease which most often affects dogs and is rare in cats. Bilateral symmetrical hair loss and excessive scaling around the the face, head, ears, and trunk are common presentations. Some dogs may develop a bald "rat tail." Often a secondary bacterial infection of the skin with papules, crusting, and odor will occur. The hairs of affected animals often have surface debris, called follicular casts, surrounding the base of the hair. Sebaceous adenitis is usually not itchy unless accompanied by a secondary infection. Definitive diagnosis is made by taking a skin biopsy and submitting to a dermapathologist for analysis.

Canine Flank Alopecia (also known as Seasonal Flank Alopecia) is a disorder which causes recurrent hair loss and may involve changes in melatonin and hormone production which affect hair follicles. Common clinical signs are non-inflammatory, non-pruritic hair loss on the flanks and may include darkening of exposed skin. The amount and duration of hair loss may increase with repeated cycles and can become permanent. No systemic signs of disease are seen. As other skin disorders cause similar hair loss, those disorders must be ruled out by evaluation of skin biopsy by a dermapathologist.

Pemphigus Foliaceus is the most common autoimmune disease in dogs and cats. The problem begins when the animal's body recognizes its own skin as foreign. As a result of this abnormal immune response, the skin is damaged. The cause may be genetic, environmental, viral, and/or drug related. First signs of this disease are typically small, red spots that rapidly form a pustule, then crust. Some pets may present as depressed, lethargic, and not having an appetite. Some may also develop secondary bacterial infections as a result of the damage to the skin caused by the disease or the trauma the pet self-inflicts as they try to sooth their discomfort. Other diseases such as infection, seborrheic skin disease, and varying forms of lupus appear similar, so a doctor with extensive education in this field is critical. Biopsies sent to a specialized dermapathological laboratory are needed for confirmation of the disease.

Color Dilution Alopecia is a hereditary skin disease affecting the way pigment is distributed in the hairs. Dogs with unusual hair coloration such as blue or fawn are most often affected. Hair loss and scaly skin are the typical first signs, and in severe cases, excessive pigment clumping causes breakage of the hair shafts and abnormal or stunted hair growth. It is necessary to rule out other causes of hair loss, such as hormonal disorders or skin infections. There is no cure, thus treatment is the control of secondary skin infections.

Seborrhea is the term used to describe skin which exhibits increased dandruff, dryness, and/or oiliness. Waxy accumulation around hairs or on the skin may be seen and a rancid odor noticed. This abnormal skin is a favorable environment for overgrowth of bacteria and yeast, which results in secondary infection. Chronic allergies and hormonal disease are two causes of seborrheic changes in the skin. Properly diagnosing and treating the underlying cause of seborrhea will lead to its resolution. Once the cause is adequately controlled, signs of seborrhea should be mild or absent within several weeks to months.

Pododermatitis is skin inflammation of the feet. Many underlying disorders result in pododermatitis. The most common cause is allergies, which results in inflammation of many areas of the skin, including the feet. Other causes of pododermatitis include Demodex, fungal infections, cystic hair follicles, sterile granuloma, and autoimmune disorders. Sometimes the inflammation is limited to the feet, with no other site affected, and causes redness and an itch sensation in the feet. This incites the pet to lick and/or chew their feet, nails, and/or foot pads. Pets with pododermatitis often develop a secondary bacterial or yeast infection. Other changes which may occur include a generalized swelling of the feet or more localized swelling (nodules) between the toes. Without quick and proper treatment, these nodules will open and become draining tracts, with pus-like or bloody discharge. Scar tissue formation then makes treatment more difficult and lengthy. 

Mast Cell Tumors are the most common skin tumor in dogs. Mast cell tumors are made of many mast cells which are unstable, meaning they release their toxic granules with simple contact or even at random, creating allergic symptoms that do not correlate to any particular antigen. Growths that get suddenly larger then smaller over a 24 hour period are likely to be mast cell tumors and this phenomenon is referred to as Darier's Sign. Most mast cell tumors are notoriously invasive and require surgical excision. Diagnosis can often be made with needle aspirate and examination of the collected cells under a microscope. The granules have distinct staining characteristics leading to their recognition. An actual tissue biopsy is needed to grade the tumor, which is crucial to determining prognosis. Therapy for most mast cell tumors consists of surgery, radiation therapy, and chemotherapy. What combination of therapy is chosen depends on the extent of the spread and malignant characteristics of the tumor.

Dr. Nichols' advanced education in this field allows you the peace of mind that your pet is being expertly diagnosed and treated for these life-altering and potentially life-threatening diseases. 

Lexi loves Dr. Nichols.