Is Your Pet Constantly Scratching or Losing Fur?
Understanding Pet Skin Issues as a Responsible Owner

Scratching

Licking

Head shaking

Dry skin

Hair loss

You might dismiss it as a minor issue, but these symptoms can be red flags for skin allergies or other dermatological conditions (such as parasites, infections, or endocrine/immune-related diseases). These issues directly impact your pet's comfort, health, and quality of life. Skin problems are extremely common among pets in Hong Kong, particularly those related to parasites, infections, and allergies (food or environmental). As a responsible pet owner, understanding the causes and how to manage your pet's skin health is crucial.

Diagnosing skin disease in pets is not an instantaneous process; it requires a systematic, step-by-step approach by a veterinarian to rule out other causes before confirming the final diagnosis. This is the key to ensuring an accurate treatment plan:

• Parasites: The first step is to check for fleas, mites, etc. Common diagnostic methods include skin scrapings, tape impressions, and hair plucking examinations. If parasites are found, they must be treated thoroughly to avoid interfering with subsequent diagnostics.
• Infections: Check for bacterial (e.g., Staphylococcus), yeast (e.g., Malassezia), or fungal infections. These are confirmed through cytology, Wood’s lamp examination, or fungal cultures. Infections often cause secondary inflammation and must be controlled first.
• Food Allergies: Diagnosed through a strict elimination diet trial, such as using hydrolyzed protein or novel protein diets.
• Environmental Allergies (Atopic Dermatitis): Only diagnosed as environmental allergies after ruling out parasites, infections, and food allergies. There is no direct test; it is a diagnosis of exclusion.

Important: The entire process must be guided by a veterinarian. Do not attempt to diagnose or treat this yourself, as it may delay proper medical care.

Dietary skin issues are mainly divided into two categories: food allergies and food intolerances, which have different causes and symptoms:

• Caused by an abnormal immune system response to specific proteins (common allergens for cats and dogs include chicken, beef, dairy, and fish). Grains (e.g., corn, wheat) rarely cause allergies; unless a grain allergy is confirmed, there is no need to avoid them. Research suggests that grain-free diets may be linked to an increased risk of Dilated Cardiomyopathy (DCM) in dogs; owners should choose carefully. Symptoms include chronic, persistent itching, skin inflammation, ear infections, and sometimes soft stools or diarrhea. Even if a pet has been eating the same food for years, they can suddenly develop an allergy. Diagnosis and management require a strict, vet-guided elimination diet trial.

• Do not involve the immune system. They are usually caused by an inability to handle specific ingredients (e.g., fat content, lactose), digestive absorption issues, or individual sensitivities. Symptoms are primarily digestive, such as vomiting, flatulence, or diarrhea, with fewer skin symptoms. These are usually effectively managed with a highly digestible diet.

To confirm a food allergy, an elimination diet trial must be conducted under veterinary supervision. Before starting, control parasites and infections (topical/oral preventatives usually do not interfere with the trial and should be used regularly). Then, over a transition period of about 1 week, switch the original diet to a "hydrolyzed protein prescription diet" or a "novel protein prescription diet." During the trial, feed only the prescribed diet and water—no treats, human food, supplements, etc. The trial lasts at least 8 weeks, potentially extending to 12 weeks. A follow-up visit at around 4 weeks assesses improvement and checks if further infection control is needed, with a final evaluation at 8–12 weeks.

To identify the allergen, once symptoms have significantly improved, reintroduce previously consumed foods "one by one" (one food/single protein source at a time) to observe for recurrence. Relapse usually occurs within 1–14 days (it may take longer in cats). If symptoms return, immediately stop that food and return to the elimination diet until symptoms stabilize before trying the next challenge.

Environmental allergens—such as dust mites, pollen, mold, grass, or trees—are numerous, especially in Hong Kong’s humid climate. Symptoms can be seasonal or year-round, including itching of the ears, paws, or belly; frequent licking or biting of the feet; recurrent skin or ear infections; hair loss; or hot spots (acute moist dermatitis). Environmental allergies are often chronic, recurrent conditions that may not be "curable," but they can be managed long-term through medication, skin barrier care, allergen management, and, if necessary, allergen-specific immunotherapy (ASIT).

Because skin disease (especially atopic dermatitis) often involves inflammation, itching, a compromised skin barrier, and recurrent infections, treatment usually requires a multi-pronged approach:

• Medication (Control of Itching and Inflammation): Antihistamines, steroids (short-term), or cyclosporine. For dogs, JAK inhibitors (e.g., oclacitinib) or anti-IL-31 monoclonal antibody injections (e.g., lokivetmab) are commonly used to control itching (a veterinarian must assess suitability). For severe or recurrent cases, immunotherapy (ASIT) may be considered.
• Topical Therapy (Skin and Ear Care/Infection Control): Use medicated shampoos to clean the skin and reduce itching/infection risk; use ear cleaning solutions to manage otitis. If bacterial/yeast infections are present, your vet may prescribe topical or oral antibacterial/antifungal courses; it is crucial to complete these exactly as directed.