Dermatitis

There are 3 main types of dermatitis: 

• Atopic dermatitis – also commonly known as eczema. Some children are born with a tendency to develop this ongoing (chronic) form of dermatitis. 
• Contact dermatitis – this is caused by contact with something that irritates your skin or something that can cause an allergic reaction.
• Seborrhoeic dermatitis – this is caused by a yeast or fungus that lives on your scalp or face. Seborrhoeic dermatitis can cause dandruff.

Other less common types of dermatitis include the following:

• Varicose or gravitational dermatitis – this usually develops on both lower legs of older adults due to swelling and poor functioning of leg veins.
• Nummular dermatitis – also known as discoid eczema. Scattered coin-shaped patches start to develop following an injury to your skin and can stay there for a few months.
• Infective dermatitis – this is caused by a bacterial or fungal infection.

Atopic dermatitis (eczema)

Atopic dermatitis (also known as eczema) affects the face and skin creases of about 15% of infants and young children. Commonly affected areas are behind the knee and inside the elbow. These areas tend to be very dry and itchy. Scratching is a common problem, and it can lead to further itchiness, broken skin and skin infections.

Atopic dermatitis is often made worse by:

• hot conditions (such as warm weather and hot baths)
• soaps and perfumes
• woollen clothing
• dust or pets.

The cause is unknown and there is no permanent cure. However, it can usually be controlled by self-care measures and regular use of creams. Eczema generally improves with time. Most children grow out of it but it can recur, particularly if the skin is exposed to irritants later in life. Read more about eczema.

Contact dermatitis

There are 2 types of contact dermatitis: irritant contact dermatitis and allergic contact dermatitis.

Irritant contact dermatitis 

Irritant contact dermatitis can happen when your skin is repeatedly in contact with irritants such as detergents, skin cleansers, acids or alkalis, solvents or other products. Repeated contact with these products can dry the skin and break down its protective layers. Irritant contact dermatitis usually affects your hands.

People whose job involves regular exposure to skin irritants are at higher risk of developing this type of dermatitis. Irritant contact dermatitis is particularly common among nurses and hairdressers (soaps, hot water, shampoos), builders and cleaners (solvents) and motor mechanics.

Allergic contact dermatitis

Allergic contact dermatitis is much less common. It affects people who become over-sensitive or allergic to contact with certain everyday substances, even very occasionally. This differs from irritant contact dermatitis where regular contact with a range of irritants is the problem.

When you touch a substance you are allergic to, your body's immune system reacts to form a rash at the point of contact (usually the hands). This rash may spread, making it difficult to know where it started and what caused it. Only substances that you are allergic to will cause this. Some of these allergens include nickel in jewellery, latex in rubber gloves, clothing elastic, medical strapping and plasters.

Causes of dermatitis depend on its type. These include:

• genetics or inherited factors, eg, you are more likely to get atopic dermatitis if you have family/whānau members with eczema, asthma or hay fever
• irritants, eg, detergents, solvents, soaps or scented household products can cause irritant contact dermatitis
• substances causing allergy, eg, nickel in jewellery, latex rubber or plants can cause allergic contact dermatitis. Allergy to the preservative methylisothiazolinone has become very common since 2016. It's used in cosmetics and household products, eg, moist wipes, shampoos, cleaners and liquid laundry products. Read more about methylisothiazolinone(external link).
• intolerance or allergy to certain foods, eg, cow's milk, wheat or gluten
• dry skin
• a skin infection, eg, in infective dermatitis
• a skin injury.

Symptoms depend on the type of dermatitis. Common symptoms include:

• dry, crusty or flaky skin
• scaly patches
• ulcers
• redness of your skin
• itchiness
• thickening and hardening skin
• stinging or painful skin rash
• skin blisters
• oozing or bleeding of your skin when scratched
• skin swelling
• a skin rash.

There are many other skin conditions that can cause similar symptoms to dermatitis, so it is important to see your healthcare provider to get a proper diagnosis.

Your doctor or nurse will ask you some questions about your symptoms and have a look at your skin. You may need to try a cream or medicine, have a skin test for allergies or have skin or nail scrapings taken to test for infections. Depending on what your doctor thinks is the cause, you may need further testing or to be referred to a dermatologist (a specialist skin doctor).

Treatment depends on the type of dermatitis. Treatments include:

• self-care
• topical medicines, eg, creams or ointments applied to the skin
• systemic or oral medicines (taken by mouth)
• phototherapy or light therapy.

Self-care

Do these self-care measures at home:

• Avoid irritants – protect your skin by avoiding irritants such as detergents, chemicals and dust. Skin can also get irritated when it is in water for too long, particularly hot water, so keep your skin dry whenever possible, eg, use gloves when washing dishes.
• Gently clean your skin – it is best to shower or bath in lukewarm water. Use a soap-free cleanser and pat yourself dry rather than rubbing your skin.
• Use moisturisers or emollients – apply liberally (lots) and frequently (at least once daily) to your affected skin. These are available over-the-counter in your local pharmacy and some can be bought in supermarkets. Ask your doctor or pharmacist if you are not sure which type is best for you.
• Don't scratch – scratching can make itching and inflammation worse, and increase your risk of getting a skin infection.
• Avoid overheating your skin – keep your space at a cool temperature.
• Apply topical creams and take any medicines as advised and prescribed by your doctor.
• If your dermatitis is caused by household or workplace irritants, you may not be able to avoid them. Using barrier creams or gloves may help protect your skin.

Topical medicines

These are creams or ointments prescribed by your doctor to put on your affected skin. Commonly prescribed topical medicines include:

• Topical steroids – there are many different strengths of steroid creams to be used for different areas of your skin.
• Pimecrolimus cream – this is a non-steroid cream that is used when steroid creams are not suitable.

Steroid creams

Hydrocortisone is a mild steroid cream that you can buy without a prescription at your pharmacy. There are many stronger ones that may be prescribed by your healthcare provider if your skin condition needs them. You may be given more than one cream. Make sure you understand how to use each one, and:

• use according to your doctor or pharmacist’s advice
• apply only where recommended and not to broken skin
• use sparingly – overuse can cause your skin to thin
• use carefully in children or if applied to your face.

Ask for specific instructions on how to use your steroid creams. Important things to know are: which one, where, when, how often and for how long. Read more about steroid creams.

Systemic or oral medicines

Certain types of dermatitis may require oral medicines (taken by mouth), including:

• antibiotics – antibiotics may be prescribed if you have a skin infection on top of your dermatitis
• methotrexate
• azathioprine
• ciclosporin
• mycophenolate. 

Phototherapy or light therapy

Phototherapy or light therapy uses light to treat dermatitis. Examples include ultraviolet B light or psoralen plus UVA light (PUVA). Talk to your doctor to find out the best treatment option for you.