How Chronic Stress Affects Coat Quality & Shedding Cycles

A science-based guide for professional groomers

By Nathalie Doaré--Ariey-Jouglard

Introduction

When a dog arrives at the salon with dull coat, excessive shedding, dandruff or greasiness, most groomers instinctively look for external causes: product choice, grooming frequency, nutrition, seasonality.But there is one major factor that often goes unnoticed, yet profoundly impacts coat quality:

-> Chronic stress.

Modern research in dermatology and behavioural science demonstrates that long-term stress alters the dog’s skin barrier, immune functions, sebum production, hair cycle, and even the microscopic architecture of the coat. For groomers, understanding this link is essential to providing adapted care, interpreting coat changes, and educating owners with accuracy and professionalism.

This article explains how and why chronic stress transforms coat quality, and what groomers can observe, prevent and support during grooming sessions.

Chronic Stress Is Not “Behavioural”, It Is Physiological

When a dog is stressed over long periods, his body enters a state of persistent HPA-axis activation (Hypothalamic–Pituitary–Adrenal axis). This releases cortisol continuously, leading to:

• immune dysregulation

• altered skin barrier (TEWL↑, hydration↓)

• inflammatory reactions

• changes in sebum production

• disrupted hair growth cycles

Chronic stress does not only affect behaviour, it affects the entire integumentary system (skin + coat).

For groomers, this means:

A stressed dog will physically show signs in the coat long before behaviour becomes obvious.

How Chronic Stress Alters the Hair Cycle

Hair does not grow continuously. It follows a 5-phase cycle:

1. Anagen — Active Growth

The follicle produces a new hair shaft.

2. Catagen — Transition

Cell division stops and the follicle begins to shrink, preparing for rest.

3. Telogen — Resting Phase

The fully formed hair remains anchored in the follicle without growing.

4. Exogen — Shedding

The old hair is released and falls out naturally or during grooming.

5. Kenogen — Empty Resting Follicle

The follicle remains empty for a variable period before re-entering Anagen.Kenogen may be prolonged in dogs experiencing chronic stress, resulting in thinner coat density.

Chronic stress disrupts these phases by:

✔ Increasing early transition into Telogen

The hair “rests” too soon.

✔ Triggering premature Exogen

Hair sheds faster and more abundantly.

✔ Shortening Anagen (growth) phases

New coat becomes shorter, weaker, and less dense.

✔ Creating asynchronous cycles

Instead of shedding in predictable seasonal waves, the dog sheds constantly.

This is why stressed dogs may show:

• continuous shedding throughout the year

• thinning coat

• slow regrowth after clipping

• bald patches

• texture changes (dry, brittle or greasy)

Stress-Induced Sebum Dysregulation

Cortisol influences the sebaceous glands, responsible for producing the oils that protect skin and coat.

Under chronic stress, sebum becomes:

🟡 Overproduced

→ greasy coat→ strong smell→ seborrhea

or

🔵 Underproduced

→ dry coat→ flaking (dandruff)→ fragile hair shafts→ rough texture

Both extremes appear frequently in grooming salons and are sometimes misinterpreted as:

• poor hygiene

• wrong shampoo

• incorrect grooming routine

• food allergy

…but in cases, the root cause is emotional and physiological stress.

Impact on Skin Barrier & Inflammation

Chronic stress weakens the skin barrier function, increasing:

• TEWL (Transepidermal Water Loss)

• susceptibility to irritants

• dryness and itching

• micro-inflammations under the coat

• bacterial and yeast imbalance

A weak barrier = a reactive coat.

Groomers may observe:

• powdery flakes

• redness after shampoo

• hypersensitivity during brushing

• areas that stay greasy even after cleaning

• repeated skin flare-ups

Stress, Nutrition & Coat Quality: The Hidden Triangle

Stress affects digestion and nutrient absorption.This indirectly leads to deficiencies in:

• omega-3

• amino acids

• B vitamins

• minerals used for hair structure

Result:💬 “This dog eats well, but his coat still looks bad.”

Groomers see this constantly and stress is often the missing link.

Behavioural Signs That Suggest Stress-Based Coat Changes

Before even touching the coat, groomers can detect chronic stress through:

Subtle behavioural indicators

• hypervigilance

• excessive panting

• trembling

• freezing

• difficulty relaxing on the table

• compulsive licking spots

• easy irritability

• jumpiness to touch or noise

Owner-reported signs

• “He’s shedding all year.”

• “He lost a lot of hair recently.”

• “His coat became greasy out of nowhere.”

• “His skin keeps flaring up.”

Behaviour + coat changes = strong indicator of chronic stress.

How Groomers Can Support Stressed Dogs

Groomers cannot “fix” chronic stress but they can significantly improve the dog’s experience and coat health.

✔ Create a sensory-safe environment

• reduce dryer noise

• avoid strong fragrances

• dim harsh lights

• decrease visual clutter

✔ Adopt predictable handling

• slow movements

• rhythmic touch

• warm hands

• clear transitions between grooming steps

✔ Avoid overstimulation

• limit excessive talking

• avoid sudden changes

• keep a steady pace

✔ Use gentle, physiological products

• mild cleansers

• supportive botanical masks

• pH-appropriate for dogs

• avoid stripping shampoos

✔ Educate owners

A crucial role of professional groomers:

“Stress affects your dog’s coat. Improving emotional stability will also improve skin and hair health.”

Owners often believe the coat problem began at the salon, when the cause is emotional overload at home, lifestyle factors, or chronic underlying stress.

When to Recommend a Veterinary Evaluation

Chronic stress can mask or overlap with medical conditions.Refer the dog to a vet when you observe:

• sudden or extreme hair loss

• large bald patches

• persistent oily or flaky coat

• redness or inflamed skin

• repeated hotspots

• slow regrowth after clipping

• coat deterioration despite correct grooming

Always document what you see; owners appreciate professional observations.

Conclusion

Coat quality is not just cosmetic, it is a window into a dog’s emotional and physiological health.

Chronic stress disrupts:

• hair cycle

• sebum balance

• skin barrier

• immune function

• shedding patterns

For groomers, recognising these signs allows better care, better communication with owners, and a more scientific, welfare-oriented practice.

Stress leaves fingerprints on the coat and the grooming table is often the first place where these clues appear.