Dog Losing Hair in Patches and Scabs: Causes, Diagnosis, and TreatmentÂ

Worse than watching your dog lose clumps of hair or develop scabby crusts is not easily imagined. Scabbing and patchy shedding (alopecia) are among the most prevalent skin problems, with a staggering array of causes—some trivial and simple to resolve, others more serious and requiring vet appointments.Â
What Does It Mean When a Dog Loses Hair in Patches with Scabs?Â

Hair loss (alopecia) in dogs refers to part or all hair loss in an area where there should be hair. Where there are scabs, this is most commonly due to:
- Skin infection or inflammation
- Trauma (scratching, biting)
- Underlying skin diseaseÂ
Scabs are a secondary effect of healing healthy skin; suspected causes are scratching, bleeding, or oozing. Where there are bald patches if they do appear before these, then that’s an irritant or sickness enough to make your dog bite and scratch repeatedly.Â
Dog Losing Hair in Patches and Scabs: Common CausesÂ

There are many possible reasons ranging from possibly life-threatening systemic illness to harmless irritation.Â
1. Fleas and Flea Allergy DermatitisÂ
- Primary cause of patchy hair loss and scabbingÂ
- Flea saliva is an allergen but a very scratchy inducerÂ
- Scabs to be expected in the base of the tail, belly, inner thighs, and backÂ
2. Mites (Mange)Â
- Sarcoptic mange (scabies) and demodectic mange are causes of hair loss and scabsÂ
- Sarcoptic mange is highly contagious and very itchyÂ
- Affects multiple areas like the ears, elbows, chest, and legsÂ
3. Fungal or Bacterial InfectionsÂ
- Staph infections form pustules that crust to form scabsÂ
- Ringworm (fungal) forms ring-patterned patches of hair loss with crusting and scalingÂ
- Often on the face, paws, and legsÂ
4. Food or Environmental AllergiesÂ
- Recurring skin inflammation due to pollen, dust mite, or food allergyÂ
- Excessive licking and chewing leading to hair loss and soresÂ
- Usually on the paws, feet, belly, ears, muzzleÂ
5. Hot Spots (Acute Moist Dermatitis)Â
- Red, wet, inflamed lesionÂ
- Scabs immediately if skin becomes dry or infectedÂ
- Secondary to local irritation of one area, most often due to licking or scratchingÂ
6. Hormonal imbalancesÂ
- Bilateral hair loss secondary to disease such as Cushing’s disease or hypothyroidism
- Can be secondary infections of exposed skin
- Typically affects tail, flanks, and neckÂ
7. Autoimmune diseasesÂ
- Lupus, pemphigus-type autoimmune dermatitis can cause ulceration, crusting, alopeciaÂ
- Most likely to affect nose, face, ears, and feetÂ
- Rare but very threatening and ought to be treated by an expertÂ
8. Contact DermatitisÂ
- Shampoo, lawn chemical, or cleanser irritant to the skinÂ
- Red, itchy rashes that crust when they are healingÂ
- Where coat is in contact with irritants (belly, paws, chest)Â
9. Poor NutritionÂ
- Malnutrition of protein, zinc, or omega-3 fatty acids will result in poor skin
- Can result in dull coat, hair loss, and secondary infectionÂ
10. Stress or Behavioral Problem (Psychogenic Alopecia)Â
- Anxiety and boredom will result in chewing, licking, or excessive grooming of caninesÂ
- Produces redness of the hair initially without subsequent development of secondary cutaneous disease but ultimately causes scabbing due to traumaÂ
Problem Identification: What to Look Out ForÂ

Etiology can be determined by virtue of being known regarding something in respect of the symptoms of it.Â
Normal Accompanying Signs:Â
- Excessive licking and scrathingÂ
- Red skinÂ
- Ring-type alopecia (cirsoid alopecia)Â
- Foul odor on skinÂ
- Scabs or scabby lesionsÂ
- Oozing or pusÂ
- Thickening or darkening of the skin
- Change in behavior (irritability, lethargy)Â
Pattern and location of hair loss might be an indication:
- Tail/back: Flea allergy most typically
- Ears and face: Mange or fungusÂ
- Paws and legs: Allergic reaction or stress
- Symmetrical loss of hair: Imbalance in endocrine systemÂ
Veterinarians Diagnose Canine Hair Loss with Scabs

As there are so many possible causes and everything looks so alike, an accurate diagnosis normally is a step-by-step one.
It is a process using a series of items which eliminate one cause after another.Â
Diagnostic Processes
1. Physical ExaminationÂ
- Examines for texture of skin, condition of coat, and distribution of lesionsÂ
2. Skin ScrapingsÂ
- Microscopically diagnoses mites-like parasiteÂ
3. Wood’s Lamp Test or Fungal CultureÂ
- Diagnoses ringwormÂ
4. Cytology (Impression or Skin Swab)Â
- Microscopic examination of cell, bacteria, and yeast cellÂ
5. Allergy TestÂ
- Blood test or intradermal test for allergy identificationÂ
6. Thyroid Testing and Blood WorkÂ
- Attempt to identify systemic disease or hormonal imbalanceÂ
7. BiopsyÂ
- Severe, chronic skin disease (e.g., autoimmune disease)Â
My Dog losing his hair in Patches and Scabs: Treatment Based on CauseÂ

When the cause is identified, treatment can proceed.Â
For Fleas and ParasitesÂ
- Prescription preventatives (Simparica, Bravecto, NexGard)Â
- Topicals and medicated shampoosÂ
- Environmental treatment and cleaningÂ
For InfectionsÂ
- Topical or oral antibiotics for bacterial infection
- Fungal medications for ringworm or yeast infection
- Medicated shampoos with Chlorhexidine, miconazole, or ketoconazoleÂ
For AllergiesÂ
- Apoquel or Cytopoint injections for relief from long-term itchingÂ
- Hypoallergenic diet trials or elimination diet trialsÂ
For Hormonal DisordersÂ
- Thyroid hormone replacement therapy in hypothyroidismÂ
- Trilostane or mitotane in Cushing’s diseaseÂ
- Regular blood testsÂ
For Autoimmune DiseasesÂ
- Immunosuppressive therapy (cyclosporine, prednisone)Â
- Specialist monitoring and regular blood testsÂ
For Behavioral IssuesÂ
- Training or enrichment exerciseÂ
- Anti-anxiety drug (clomipramine, fluoxetine)Â
- Increased physical exercise and stimulationÂ
Home Care & Prevention Tips to Allow Your Dog to RecoverÂ
Regardless of diagnosis, supportive home remedies on its own can permit recovery.Â
Do’sÂ
- Use vet-approved hypoallergenic shampoosÂ
- Bathe and dry your dog’s bedding
- Wear a cone collar to discourage scratching or lickingÂ
- Eat a high-quality diet with plenty of omega-3s and zincÂ
- Apply topical sprays or balms to itchy and healingÂ
Don’tsÂ
- Apply human cream or meds (all toxic to dogs)Â
- Do internet picture diagnosis on themselvesÂ
- Wait until it’s worse to come in to see the vetÂ
When to See Your Vet Right AwayÂ
The majority of minor skin issues will cure on their own, but some signs must be addressed immediately by a vet:
- Abrupt, coarse sheddingÂ
- Oozing, bleeding, or open soresÂ
- Over-scabbingÂ
- Pain or discomfortÂ
- Redness or pusÂ
- Weight loss or loss of appetiteÂ
- Failure to call within 7–10 days at homeÂ
Early intervention will prevent complications and scarring of the skin.
Prevention of Patchy Hair Loss and Prevention of ScabbingÂ

Prevention is always preferable to a cure. Here’s how much it’ll cost to protect your dog’s coat and skin:Â
Routine Preventative CareÂ
- Monthly routine flea, tick, and mite preventativesÂ
- Frequent routine vet visits and blood workÂ
- Coat and skin inspection and grooming dailyÂ
DietÂ
- Prescription dietÂ
- Medication like fish oil, biotin, and zinc
HygieneÂ
- Dog shampoo bath only (excessive bathing is not healthy)Â
- Daily cleaning of ears to avoid infectionÂ
- Trimming of fur around the paws and groin for cleanlinessÂ
Mental WellbeingÂ
- Ongoing exercise, stimulation, toysÂ
- Help to reduce stress, noise, and change of environment shockÂ
Know, Act, and HelpÂ
Scabbing and patchy shedding are more than skin issues—more likely, signs of disease or stress somewhere deeper.
Whatever the cause, be it something as mundane as fleas or something as malevolent as an autoimmune disease, treatment and early diagnosis are in order.
Be vigilant. Observe any alteration of coat, temperament, or skin of your dog. With good care under the guidance of the veterinarian, good diet, and proper housing, most dogs grow a normal coat.
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