What are the common causes of dermatitis in dogs and cats?

Common causes of dermatitis in dogs and cats include allergic reactions, parasites, bacterial or yeast infections, hormonal imbalances, and diet-related issues. A vet must confirm the cause through examination and testing before arranging treatment.

What can I do at home to relieve my pet's symptoms?

Keep the affected area clean and dry, avoid harsh cleansers, and discourage frequent scratching or licking. Monitor for changes; if symptoms do not improve or worsen, seek veterinary attention promptly.

What information should I bring to a dermatology appointment?

Bring close-up and full-body photos of the lesions, a record of when symptoms began, recent diet and environmental changes, and a list of current or past medications and any previous test results to help the vet assess the situation quickly.

Is a skin biopsy painful or risky?

A skin biopsy may require local or brief general anaesthesia. There is some discomfort, but it is manageable. Your vet will explain the risks and pre-procedure instructions; whether to proceed should be decided in discussion with your vet.

How much do the tests and treatment usually cost?

Costs vary by clinic and region — ask your vet for an estimate before proceeding.

Disease Guide

Canine & Feline Dermatitis: Symptoms, Diagnosis & Home Care [2025]

Dermatomyositis is an autoimmune disease affecting the skin and muscles, most commonly seen in certain dog breeds, and requires immunosuppressive treatment.

Take 1 minute to check the symptoms first

Last updated: 2026/01/05

Pethealthmap Editorial Team

Sources: WSAVA, National Taiwan University Veterinary Hospital

When to See a Vet

Seek Immediate Emergency Care

•Severe persistent itching that prevents eating or resting
•Heavy bleeding or discharge from the skin that cannot be stopped
•Large areas of ulceration, severe necrosis, or rapidly spreading skin lesions

Schedule a Clinic Visit Soon (within 24–72 hours)

•Localized hair loss with repeated scratching that worsens at night
•Skin redness, swelling, or crusting that shows no improvement after several days
•Noticeable odor, discharge, or a significant increase in flaking/dandruff

01What Symptoms Indicate a Problem?

Skin inflammation in dogs and cats commonly presents as hair loss, intense itching, redness, swelling, or crusting, and may be accompanied by dandruff, odour, or discharge. The extent and severity of symptoms can affect daily life and appetite.

Patchy or extensive hair loss with noticeably thinning coat
Frequent scratching, licking, or biting at the same area
Redness, swelling, crusting, or changes in skin pigmentation
Increased dandruff or an unusual odour from the skin
Skin ulcers, oozing, or discharge
If symptoms persist or worsen, seek a veterinary assessment promptly

02How to Assess Abnormalities at Home: Key Observations and Emergency Criteria

Observing and documenting details at home helps your vet quickly identify the cause and treatment direction — photos and written records are more useful than verbal descriptions alone.

Use your phone to take close-up and full-body photos of the affected area for your records
Note when symptoms first appeared and how frequently they change
Record daily changes in appetite, energy levels, and sleep
Weigh your pet regularly and track weight trends
Monitor for any changes in toileting habits or activity levels
Record any exposure to new foods, medications, or environmental changes

03How Will the Vet Make a Diagnosis? Common Examination Steps

Your vet will begin with a physical examination and, if needed, run tests or imaging to identify infection, allergies, or other underlying systemic causes.

Physical examination

detailed inspection of the skin, hair follicles, and distribution of lesions

Blood test

assessing general inflammation or infection markers

Biochemistry panel

evaluating liver, kidney, and other organ function

Urinalysis

ruling out systemic disease or metabolic abnormalities

Skin sampling or biopsy

clarifying the pathology and causative agent

Advanced imaging (if required) to assess deeper or systemic lesions

04Post-Diagnosis Treatment and Care: Medications, Diet, and Home Management

After treatment for skin disease, close monitoring and regular follow-up visits are essential to adjust medications or repeat tests. Some causes require long-term ongoing management.

Administer medications as prescribed and record your pet's clinical response
Implement an elimination diet or dietary adjustment as directed
Keep your pet's bedding and activity areas clean and free of irritants
Short-term hospitalisation for observation or localised treatment may be required if necessary
Attend regular follow-up appointments to monitor skin condition and repeat blood or other tests
Some underlying causes require long-term follow-up in collaboration with a veterinary dermatology specialist

05What to Prepare Before the Vet Visit: Key Information to Help Your Vet Quickly Identify the Cause

Take and bring close-up and full-body photos of the affected area

Note the time of first onset and any record of how symptoms have changed

Record the frequency of scratching, licking, biting, or any behavioural changes

List recent diet changes, environmental changes, and anything your pet has been in contact with

Bring a list of current medications and supplements, along with any previous test results

Consider booking an appointment at a clinic with veterinary dermatology expertise

This content is for reference only and cannot replace a professional veterinary diagnosis. If your pet shows signs of illness, please seek veterinary care promptly.