Contact Dermatitis: Symptoms, Causes and Treatment
Contact dermatitis is an inflammatory skin condition caused by direct contact with certain substances. It is one of the most common skin conditions, accounting for about 20% of all inflammatory skin disease, and it affects both daily life and the workplace. Understanding the causes and how to prevent them can effectively reduce flare-ups.
What is contact dermatitis?
Contact dermatitis is divided into 2 main types:
Irritant contact dermatitis (ICD): The most common type, accounting for about 80% of all contact dermatitis. It is caused by substances that damage the skin directly without involving an allergic process, such as soap, detergent, cleaning products, acids, alkalis and other chemicals.
Allergic contact dermatitis (ACD): Caused by an immune response to an allergen, which requires repeated contact before symptoms appear. Once the skin has "remembered" the substance, it reacts more strongly every time it is touched again.
Common allergens
Nickel: In jewelry and various metals.
Fragrance: Perfumes and scenting agents in products.
Rubber/latex: Natural rubber and latex.
Hair dye/preservatives: Hair dye (paraphenylenediamine or PPD) and preservatives in cosmetics.
Others: Certain plants, cosmetics, and materials in shoes or clothing.
Symptoms of contact dermatitis
Common symptoms include a red rash, itching, burning, swelling, dry cracked skin, clear blisters and peeling skin. In severe cases there may be oozing. Symptoms usually appear where the substance touched the skin directly, such as the hands, arms, neck, face, or areas where jewelry is worn.
Diagnosis and treatment
A dermatologist will make the diagnosis by taking a history of substance exposure, and may perform a patch test to identify the specific allergen. Treatment includes:
Avoid the substance: Avoiding the trigger is the most important step.
Anti-inflammatory topical medication: Topical corticosteroids to reduce inflammation, as advised by your doctor.
Itch relief: Antihistamines to relieve itching.
Skin repair: Moisturizers to add hydration and repair the skin barrier. Severe cases may need oral or injectable medication.
How to prevent contact dermatitis
Avoid: Strictly avoid substances you are allergic to.
Protect yourself at work: Wear gloves when handling chemicals.
Choose products: Choose products free of allergenic ingredients (hypoallergenic).
Skin care: Rinse the skin with plain water after contact with a substance, and apply moisturizer regularly to strengthen the skin barrier.
Frequently asked questions
Can contact dermatitis be cured? If you can strictly avoid the substance you are allergic to, symptoms usually improve and do not return. If you keep touching the same substance, the rash can come back. Identifying the true cause is therefore important for long-term control.
What is a patch test, and is it necessary? A patch test places suspected allergens on the skin of the back and reads the results afterward, helping to identify the true allergen. It suits people with a chronic rash or no clear cause.
How is it different from hives? Contact dermatitis is inflammation limited to the area that touched the substance, usually with red, peeling skin or blisters. Hives are raised, swollen welts that appear and fade quickly. Telling them apart correctly helps choose the right treatment.
If you have a chronic itchy rash or suspect an allergy to something that touches your skin, Siam Dermatology offers patch testing and treatment by a dermatologist. Call +66 61 448 7000 or LINE @siamderm.
Written by Dr. Patara Voravutinon, Dermatologist · Last reviewed July 16, 2026
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