Understanding Chronic Itching and Skin Disease in Dogs: Wells Syndrome, Allergies, and Sarcoptic Mange Explained
Chronic itching, hair loss, and skin inflammation in your dog can be frustrating and emotional, especially when symptoms appear suddenly or worsen over time. These signs can be triggered by a range of underlying conditions, and getting an accurate diagnosis often involves multiple tests and ruling out several possible causes.
Three common considerations in difficult skin cases are environmental and food allergies, sarcoptic mange (scabies), and Wells syndrome (eosinophilic dermatitis), a rare immune-mediated condition. Understanding how these conditions differ—and how they are diagnosed—helps you advocate for your dog's proper care.
1. Environmental & Food Allergies (The Most Common Culprit)
Allergies are the leading cause of chronic itching (pruritus) in dogs. When your dog is exposed to something they are allergic to, their immune system overreacts, causing inflammation of the skin. This inflammation often leads to secondary bacterial or yeast infections, which intensify the itching and discomfort.
Causes and Types:
Environmental Allergies (Atopy): These are reactions to common substances in the environment like pollen, dust mites, grass, and mold. They often start between 6 months and 3 years of age and can be seasonal or year-round.
Food Allergies: These are typically sensitivities to proteins, with common triggers including chicken, beef, dairy, and wheat. Food allergies can develop at any age and usually cause year-round symptoms.
Contact Allergies: Less common, these occur when your dog's skin comes into direct contact with an irritant, such as certain detergents, bedding materials, or topical products.
Symptoms to Watch For:
Intense itching, especially on the face, paws, belly, armpits, and rump.
Hair loss from constant chewing and licking.
Chronic ear infections, often with a yeasty odor.
Redness, hot spots, skin odor, or darkened skin over time.
Digestive issues like soft stool or gas may indicate a food sensitivity.
Diagnosis and Treatment:
Diagnosing allergies involves a process of elimination. Your vet will first rule out parasites. A skin cytology test can identify secondary yeast or bacterial infections. For food allergies, an 8–12 week elimination diet using a novel or hydrolyzed protein is the gold standard for diagnosis.
Treatment focuses on management and includes:
Strict diet management with a single-protein or hypoallergenic food.
Medications like Apoquel or Cytopoint to control itching.
Antifungal or antibiotic therapy for secondary infections.
Medicated shampoos and regular bathing to soothe the skin.
Omega-3 fatty acid supplements to support skin health.
2. Sarcoptic Mange (Scabies): The Great Imitator
Sarcoptic mange is caused by the Sarcoptes scabiei mite, a microscopic parasite that burrows into the skin. It can look nearly identical to severe allergies, making it a tricky condition to diagnose. To complicate matters, skin scrapings used to find the mites are only 20–50% accurate, meaning a negative test does not rule out scabies.
How It Spreads:
This condition is highly contagious through contact with infected dogs, wildlife (like foxes), or contaminated environments such as kennels or shared bedding. It can also be transmitted to people, causing a temporary, itchy rash.
Symptoms to Watch For:
Extreme, relentless itching that often seems worse at night.
Hair loss, particularly on the edges of the ears, elbows, hocks (ankles), belly, and chest.
Crusty ear edges, known as "pinna margin crusting."
Red bumps and thickened, leathery skin over time.
Symptoms often appear suddenly and spread rapidly.
Diagnosis and Treatment:
Due to the unreliability of skin scrapings, vets often recommend an empirical treatment trial. If the dog's symptoms improve dramatically after being treated for scabies, the diagnosis is confirmed.
Treatment requires aggressive action:
Effective medications like Revolution (selamectin) or Bravecto (fluralaner).
Treating all other pets in the household simultaneously.
Thoroughly cleaning and disinfecting all bedding, brushes, and furniture.
A short course of steroids or antibiotics may be needed to manage severe inflammation and secondary infections.
3. Wells Syndrome (Eosinophilic Dermatitis) in Dogs
Wells syndrome, also called eosinophilic cellulitis, is a rare immune-mediated skin disease. It is characterized by intense inflammation driven by eosinophils, a specific type of white blood cell. While much less common than allergies or scabies, it may be considered when other conditions have been ruled out.
What Triggers It?
The exact cause is sometimes unknown, but potential triggers can include:
Insect bites
Infections
Adverse reactions to medications or vaccines
Dietary changes
Stress
An underlying autoimmune reaction
Symptoms to Watch For:
Patchy hair loss.
Red, raised, and firm plaques on the skin.
Heat and swelling under the skin.
Crusting or ulceration in affected areas.
Itching can vary from mild to severe.
The trunk, tail, thighs, or flanks are commonly affected.
Diagnosis and Treatment:
Diagnosis requires a more in-depth workup. A complete blood count (CBC) often shows high levels of eosinophils. After ruling out parasites, a skin biopsy is necessary to confirm the diagnosis by identifying eosinophilic inflammation in the skin layers.
Treatment focuses on calming the immune response:
A short course of steroids (like prednisone) is often used initially.
Identifying and removing any potential triggers is crucial.
Omega-3 fatty acids and other immune-supporting supplements can be beneficial.
For persistent cases, medications like cyclosporine may be prescribed.
How These Conditions Compare
How These Conditions Compare
A quick side-by-side for guardians: itching severity, contagiousness, ear infections, steroid response, and the key diagnostic step.
| Feature | Allergies | Sarcoptic Mange | Wells Syndrome |
|---|---|---|---|
| Itching Level | Moderate to Severe | Severe | Mild to Severe |
| Contagious | No | Yes (to pets & people) | No |
| Ear Infections | Common (yeast) | Rare | Rare |
| Response to Steroids | Improves symptoms | Temporary relief only | Improves strongly |
| Key Diagnostic Test | Diet trial / Allergy history | Positive response to treatment | Skin biopsy |
Final Thoughts: Actionable Steps for Dog Owners
Dealing with chronic skin disease in your dog can feel overwhelming, but a methodical approach is key.
Start with Your Vet: Always begin with a thorough veterinary examination.
Rule Out Parasites: The first step is always to check for and eliminate parasites like fleas and mites.
Address Secondary Infections: Treat any existing bacterial or yeast infections to reduce inflammation.
Support the Skin Barrier: Use medicated shampoos and ensure a consistent, high-quality diet.
Investigate Further: If symptoms persist, work with your vet to pursue an elimination diet for food allergies or consider a skin biopsy if an immune-mediated disease is suspected.
By staying patient and working closely with your veterinarian, you can identify the root cause of your dog's discomfort and find a management plan that brings them lasting relief.
Conclusion: Nutrition Is the Foundation of Skin and Immune Health
No matter if your dog is battling allergies, mange, or a rare diagnosis like Wells syndrome, one element shapes their healing journey more than any other: thoughtful, balanced nutrition. Every vibrant coat and resilient immune system begins with what’s in the bowl. Proteins are especially powerful—they provide the amino acids that repair skin, fuel the immune response, and keep coats plush and healthy.
Consistent, high-quality meals—rich in animal-based proteins, omega-3s, vitamins, and minerals—build up every line of defense your dog has against skin flare-ups and inflammation. At Stokeshire, we nurture our dogs with a stable, fish-forward diet like Diamond Naturals Salmon & Potato or a similar recipe, to help their skin naturally fend off irritants and minimize allergic triggers. Constantly switching foods or skimping on protein can upset the balance your dog’s body works hard to maintain.
When you approach every meal as an act of care, you’re not just feeding a hungry pup—you’re investing in a future filled with comfort, vitality, and those unforgettable Stokeshire moments. Wholesome nutrition, offered with love and consistency, is the secret ingredient in every thriving dog’s story.