Dermatitis

Dermatitis is the inflammation of your skin. It is used as a term for a group of inflammatory skin conditions.

Key points

  1. These conditions can cause red, itchy, crusted or dry skin that can become swollen or blistered.
  2. Examples of different types of dermatitis include atopic dermatitis (eczema), contact dermatitis, seborrheic dermatitis, varicose dermatitis, nummular dermatitis or infective dermatitis.
  3. Causes of dermatitis depend on its type, common causes include genetics, irritants, allergy, infection or injury to your skin.
  4. Treatment depends on the type of dermatitis, these may include self-care measures, topical creams, oral medicines or phototherapy.

What are the different types of dermatitis?

The main types of dermatitis include: 

  • atopic dermatitis – some children are born with a tendency to develop this  ongoing (chronic) form of dermatitis. Atopic dermatitis is also commonly known as eczema.  
  • contact dermatitis – this type of dermatitis is caused by contact with something that irritates your skin or something that can cause an allergic reaction.
  • seborrheic dermatitis – this is caused by the irritation from toxic substances produced by a yeast or fungus that live on your scalp or face. Seborrheic dermatitis is also known as dandruff.

Other less common types of dermatitis include:

  • varicose or gravitational dermatitis – this type of dermatitis usually develops on both lower legs of older adults due to swelling and poor functioning of leg veins.
  • nummular dermatitis – nummular dermatitis is also called 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) tends to affect 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 appropriate advice and treatment. 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 forms of contact dermatitis, these include irritant contact dermatitis and allergic contact dermatitis.

Irritant contact dermatitis 

Irritant contact dermatitis is often caused by repeated contact with irritants such as detergents, skin cleansers, acids or alkalis, solvents or other products. Such contact eventually dries the skin and breaks down its protective layers. Irritant contact dermatitis usually affects the hands.

Certain occupations which involve exposure to irritants as an everyday part of the job can make people more prone to 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.

What are the causes of dermatitis?

Causes of dermatitis depends on its type. These include:

  • genetics or inherited factors, eg, you are more likely to get atopic dermatitis if you have   family members with eczema, asthma or hay fever
  • irritants  eg, detergents, solvents, soaps, scented household fragrances can cause irritant contact dermatitis
  • substances causing allergy  eg, nickel in jewellery, latex rubber or plants can cause allergic contact dermatitis
  • 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.

What are the symptoms of dermatitis?

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.

How is dermatitis diagnosed?

The cause of a rash or a scaly patch may not be obvious, letting your doctor know so that they can make a proper diagnosis is the first step. There are also many other skin conditions that can cause similar symptoms to dermatitis.

Your doctor 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 other infections. Depending on whether what your doctor thinks is the cause, you may need further testing or be referred to a dermatologist (a skin doctor).

How is dermatitis treated? 

Treatment depends on the type of dermatitis. Treatments include:

  • self-care
  • topical medicines
  • systemic or oral medicines
  • phototherapy or light therapy.

Self-care

Some self-care measures to treat dermatitis include:

  • irritant avoidance – protect your skin by avoiding  irritants such as detergents, chemicals, dust and water.
  • gentle cleaning of your skin – it is best to shower rather than take baths in lukewarm waterand reduce how often you shower..Also use a soap-free cleanser and pat yourself dry rather than rubbing your skin.
  • using moisturisers oremollients – apply liberally and frequently (at least daily) to your affected skin. These are available over-the-counter in your local pharmacies or chemist. Ask your doctor or pharmacist if you are not sure which type is suitable for you.
  • avoid scratching – scratching can irritate your skin even more and increase your risk of getting a skin infection.
  • avoid overheating your skin – keep your space at a cool temperature.

Read more about how can I care for myself with dermatitis.

Topical medicines

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

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

Corticosteroid creams

Hydrocortisone is a weak corticosteroid. There are many stronger ones that require much more care. 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 corticosteroid creams: which one? where? when? how often, and for how long?

Read more about corticosteroid creams.

Systemic or oral medicines

Certain types of dermatitis may require oral medicines, these include:

  • antibiotics – antibiotics may be prescribed if you have a skin infection on top of your dermatitis.
  • antihistamines – antihistamines are used to help relieve itching of your skin.
  • steroid tablets
  • methotrexate
  • azathioprine
  • ciclosporin
  • mycophenolate. 

Phototherapy or light therapy

Phototherapy or light therapy is the used of light to treat dermatitis. Examples of light include ultraviolet B light or psoralen plus UVA light (PUVA).

Talk to your doctor to find out the best treatment option for you.

How can I care for myself with dermatitis?

You can help improve and protect your skin by some of the following measures:

  • Irritant or allergens avoidance – protect your skin by avoiding irritants or allergens such as detergents, chemicals, dust and water.
  • Gentle cleaning of your skin – it is best to shower rather than take baths in lukewarm water and reduce how often you shower. Also, use a soap-free cleanser and pat yourself dry rather than rubbing your skin.
  • Using moisturisers or emollients – apply liberally and frequently (at least daily) to your affected skin. These are available over-the-counter in your local pharmacies or chemist. Ask your doctor or pharmacist if you are not sure which type is suitable for you.
  • Avoid scratching your skin – scratching can irritate your skin even more and increase your risk of getting a skin infection.
  • Avoid overheating your skin – keep your space at a cool temperature.
  • Taking medicines or applying topical creams 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.

Learn more

The following links provide further information about dermatitis. Be aware that websites from other countries may have information that differs from New Zealand recommendations.   

Dermatitis DermNet New Zealand
A guide to the use of topical treatment Healthinfo Canterbury, NZ
Dermatitis Cleveland Clinic, US
Dermatitis Mayo Clinic, US 

References

  1. Eczema or dermatitis in adults 3D Regional HealthPathways, NZ, 2021
  2. Dermatitis DermNet New Zealand

 

Credits: Health Navigator, Oct 2014.