Dog Itching and Skin Problems: What to Track

Skin problems in dogs are among the most common presentations in veterinary practice - and among the most frustrating to diagnose. Not because the conditions are mysterious, but because the same symptoms (itching, redness, recurring ear infections, paw-chewing) can be driven by completely different causes, and distinguishing between them requires pattern recognition that the owner is far better placed to provide than the vet. The PDSA PAW Mini Report 2025 identified skin and coat problems as a leading welfare concern in UK dogs, with flea allergy dermatitis alone accounting for a significant proportion of dermatology cases seen in general practice.

The difference between a dog who itches only in summer and one who itches year-round is the difference between environmental allergy and food allergy. A vet examining the dog in September can't determine which of those it is. You can, if you've been recording it.

The diagnostic challenge

Allergic skin disease in dogs - formally called canine atopic dermatitis - is driven by environmental allergens (grass pollen, house dust mites, storage mites, mould spores), food allergens (most commonly beef, dairy, chicken, wheat), or contact allergens (cleaning products, certain plants). It can also be complicated by secondary bacterial or yeast infections that develop on already-irritated skin.

These causes overlap and interact. A dog might have an underlying food sensitivity that makes their skin barrier more reactive, compounded by seasonal pollen, compounded by a yeast infection that develops because the skin is already compromised. Unpicking this requires knowing the history: when it started, what season, how it's changed, whether diet changes made any difference.

What to log

When you notice skin symptoms, record:

• Date first noticed
• Where on the body - face, ears, paws, groin, armpits, belly, tail base
• What the symptoms look like - redness, hair loss, thickened or darkened skin, scabbing, discharge
• Severity - how much the dog is scratching, licking, or chewing
• Season - what time of year it is, what the weather has been like
• Recent changes - new food, new treats, new cleaning products in the house, new bedding, new garden plants, new flea treatment brand, new shampoo
• Ear status - many atopic dogs also have recurring ear infections; note any head-shaking, scratching at ears, dark discharge

Photographs are extremely useful. A photo of the affected area, dated, is far more useful to a vet than a verbal description - and a series of photos over time shows whether things are improving, static, or worsening.

Seasonal vs year-round

Seasonal itching - starts in spring or summer, improves or resolves in winter - strongly suggests environmental allergy. Common culprits are grass pollen (May–August), tree pollen (spring), and mould spores (late summer/autumn). Many dogs are allergic to house dust mites, which peak indoors in autumn and winter when heating is on and ventilation is reduced.

Year-round itching with no seasonal pattern - same in January as in July - is more consistent with food allergy, or house dust mites in a heated home, or a combination.

If you've been logging the pattern for a year, this distinction is immediately clear. If you haven't, you're trying to reconstruct it from memory, which is much harder.

Food allergy and elimination diets

If food allergy is suspected, the definitive test is a strict elimination diet - typically 8–12 weeks on a novel protein (one your dog has never eaten before, such as venison or duck) or a hydrolysed protein diet. During this period, no treats, no table scraps, no flavoured medications, no dental chews - anything with a protein source that isn't the test diet undermines the trial.

Keeping a log during an elimination diet is essential. You need to record exactly what the dog ate each day, whether symptoms improved and when, and any accidental exposures to other foods. Without this record, it's impossible to interpret the results accurately.

Parasite-related skin problems

For full monitoring guides on the most common skin conditions, see: skin allergies (atopic dermatitis), food allergies, hot spots, mange, and ringworm.

Fleas are the most common cause of skin disease in dogs globally and the most common cause of itching. Flea allergy dermatitis is a reaction to flea saliva - a single flea bite causes intense itching in allergic dogs, and you may never see the flea itself because the dog grooms them off. Classic distribution: base of tail, lower back, inner thighs.

If you're not treating for fleas consistently and on schedule, rule this out before going further. Note your flea treatment product and dates in your health log - "I treat regularly" is different from having a record of actual treatment dates. According to NOAH (National Office of Animal Health), an estimated 1 in 7 dogs in the UK has fleas at any given time - yet the PDSA PAW Mini Report 2025 found that around 19% of UK dog owners do not treat their dogs for fleas at all, making flea-related skin disease highly preventable.

Sarcoptic mange (scabies) causes intense, often sudden itching, commonly on the ear margins, elbows, and hocks. It's highly contagious to other dogs and to people. If the itching is severe and sudden-onset, mention this possibility to your vet.

When to see the vet

• Itching that's been going on more than two weeks without obvious cause
• Any skin infection signs - yellow or green discharge, crusting, a bad smell, visible sores
• Severe or escalating itching that's clearly distressing the dog
• Ear infections (dark discharge, smell, head-shaking) alongside skin itching - usually indicates atopic disease
• Any time you're not sure what's causing it

Frequently Asked Questions

My dog is always licking their paws. Is that normal? Occasional paw licking is normal. Persistent or compulsive paw licking - to the point of redness, hair loss, or skin changes between the toes - is not. It's most commonly a sign of atopic dermatitis or food allergy and warrants investigation if it's been going on for more than a few weeks.

Can dogs be allergic to grass? Yes. Grass pollen allergy is one of the most common environmental allergies in dogs. It typically causes seasonal itching - worse in spring and summer - affecting the paws, face, ears, and belly. Management options include immunotherapy, medications, and regular foot washing after walks on grass.

Are antihistamines useful for dog allergies? Less so than in humans - antihistamines work reasonably well in people but have variable efficacy in dogs, with studies suggesting they help around 30% of dogs. They're safe and worth trying in mild cases. For more significant atopic dermatitis, oclacitinib (Apoquel) and biologics like lokivetmab (Cytopoint) are more consistently effective. Your vet can advise.

Does diet affect skin problems? Yes, in multiple ways. True food allergy causes skin inflammation. More broadly, diet affects skin barrier function - diets deficient in essential fatty acids produce drier, more reactive skin. Some dogs with atopic dermatitis show improvement on higher omega-3 diets. This doesn't mean switching food solves everything, but it's a valid part of the conversation with your vet.