Symptoms vary depending on the type of dermatitis. They may include a rash that oozes, weeps clear fluid or bleeds if you scratch it.
Your healthcare provider will examine your skin and ask you about your symptoms and health history. For example, atopic dermatitis is often linked to allergies and asthma, and seborrheic dermatitis can be associated with dandruff and celiac disease (a condition that affects the digestive tract). It may also occur in children as part of the atopic march.
Causes
Dermatitis can be caused by many things. In some cases, it happens because the immune system is overactive and overreacts to seemingly small irritants or allergens. In addition, genetics and a change in a protein that helps maintain healthy skin can make you more susceptible to dermatitis.
Atopic dermatitis (eczema) is the most common form of dermatitis. It causes dry, itchy scaly patches of skin that can often appear on the face and scalp in infants. Later, it may show up on the knees, elbows, and ankles, creases of hands, and around the eyes. It also tends to run in families. Some research suggests that having atopic dermatitis in early life can lead to other health problems, such as hay fever and asthma.
Contact dermatitis occurs when the skin is exposed to substances that irritate it or cause an allergic reaction, such as poison ivy, perfume, soap, and metal jewelry, including nickel. Allergic contact dermatitis can be identified with patch testing.
Nummular dermatitis is a type of dermatitis that causes coin-shaped red patches on the legs, arms, and torso. It is more common in men than women and typically begins in middle age. It is also more common in people with light skin than those with darker skin. It is sometimes called ringworm of the skin or stasis dermatitis. It is caused by poor blood flow to the lower limbs, which leads to a buildup of fluid and skin cells that becomes itchy and inflamed.
Symptoms
Dermatitis is red skin that itches, swells or oozes. The skin may become scaly, dry or thickened, and sometimes bleeds when the itchy rash is scratched. There are many types of dermatitis, and the symptoms vary from type to type. In general, itchy skin is the most common symptom. But some people have both itching and a burning sensation, while others don’t experience any pain.
The rash can be caused by a variety of things, including substances that irritate the skin such as perfumes, soaps and metals. It can also be triggered by a skin infection (psoriasis) or health conditions such as HIV/AIDS, congestive heart failure and Parkinson’s disease. Dermatitis often affects the hands, and a type called hand eczema can make them swell and crack. Some people develop itching all over the body, while others only have a rash in certain areas such as on the face, inside the elbows and behind the knees or on the hands and feet.
Some people have a genetic tendency to get dermatitis, and the condition can get worse with age. Other risk factors include a history of allergies or asthma, a job that exposes you to chemicals or solvents, a poor diet and stress. Some forms of dermatitis, such as atopic dermatitis (eczema), can start in infancy or childhood, and others, such as contact dermatitis from poison ivy, can occur at any age.
Diagnosis
A healthcare provider will take a close look at your skin and may ask questions about the symptoms you’re having. They’ll look for the classic signs of dermatitis, like redness, dryness and scaling. They’ll also ask about any other symptoms you’re having, such as itching or burning. Your doctor will also ask about any other health conditions you have, such as allergies or asthma, and whether you’ve been exposed to anything that might make your rash worse (like soaps, detergents or cigarette smoke).
The type of dermatitis you have will help the doctor diagnose it. For example, atopic dermatitis causes a red rash that’s often very itchy, especially at night. It typically appears on the hands and face, but can affect any part of the body. It can also cause cracks and blisters that ooze fluid.
If your GP isn’t sure what’s causing your dermatitis, they might refer you to a specialist (dermatologist). This doctor has specialized training in diagnosing and treating skin diseases. They’ll be able to narrow down the cause and prescribe treatment.
Treatment
The first step in treatment is to avoid contact with irritants. This includes avoiding soaps, shower gels and other detergents, dust and dirt, organic solvents and drying/desiccating agents, including those used in laundry or dishwashing. It is important to wash your hands frequently but gently with a mild soap or emollient cream and to use an occlusive glove for hand dermatitis. It is also useful to keep the skin moist with ointments, lotions and creams 2 or 3 times per day. This helps prevent dryness, itching and cracking.
Antihistamine medications can help reduce itching. Oral antibiotics may be prescribed to prevent infection, especially if scratching brings bacteria to the skin surface and leads to a rash. Oral cyclosporine is sometimes used to treat severe dermatitis, but this medication, originally developed to prevent rejection after organ transplantation, suppresses the immune system and can have serious side effects.
Alternative therapies such as dietary supplements, herbal remedies and homeopathy may be helpful for some people. However, the evidence for these therapies is limited and some can cause irritation or an allergic reaction. New treatments are under investigation, such as dupilumab (a monoclonal antibody), lebrikizumab and tralukinumab. These are administered as injections. They are being tested in conjunction with a skin moisturizer and emollients. Some patients with atopic dermatitis, especially those with Black and Brown skin, experience a change in skin color after treatment, either lightening (hypopigmentation) or darkening (hyperpigmentation). It can take months for this to disappear.