Eczema can occur anywhere on the body, but it is common on the backs of the knees. This is due to areas of skin rubbing against each other and moisture forming in the skin creases.

Eczema refers to a group of conditions that cause patches of itchy, dry skin. The most common type is atopic dermatitis, which often affects the knees, elbows, or hands.

This article reviews eczema on the backs of knees, symptoms, possible complications, causes, diagnosis treatments, prevention, and outlook.

The main symptom of eczema is dry, itchy skin. A person may have:

  • patches of inflamed skin
  • red, purple, brown, or gray discoloration, depending on skin tone
  • skin that is swollen or sore
  • scaly, rough, or crusty skin
  • thickening and hardening of the skin, which is known as lichenification
  • cracks or fissures if the eczema is severe

If the skin develops an infection, a person may also have pus or fluid that leaks from the area.

Eczema often develops in the creases of the skin on the knees or elbows. Doctors call this flexural eczema.

The causes of eczema behind the knees depend on the type of eczema a person has. Sometimes, it is a specific irritant or allergen, such as:

  • cosmetics
  • skin care products
  • laundry detergents

This type of eczema is known as contact dermatitis.

However, atopic dermatitis is the most common type, and its causes are unclear. It often occurs in people who have asthma or other allergies, but it is not a direct result of an allergic reaction.

Factors that may contribute to atopic dermatitis include:

  • genetics, or a family history of atopic dermatitis
  • an impaired skin barrier
  • an overactive immune system

Eczema often occurs in the creases of the skin behind the knees because the skin rubs against other skin, clothing, or other surfaces. People can also sweat behind the knees, which may lead to irritation.

However, it is also important to note that other skin conditions, such as fungal infections, can also resemble eczema and may also be common in the folds of the skin. For this reason, it is important to get a medical diagnosis from a doctor, where possible.

Triggers for eczema behind the knees

Some people with eczema have triggers that can cause or worsen a flare-up. Examples of triggers that may worsen eczema on the backs of the knees include:

  • heat
  • sweat
  • harsh or drying personal care products, such as bubble bath or body wash products
  • biological laundry detergents and fabric softeners
  • certain fabrics, such as wool or polyester
  • leather dyes, such as on a couch or car seat
  • surface cleaners and disinfectants if they make contact with the skin
  • dust mites or dirt
  • stress

Doctors may be able to diagnose atopic eczema by asking about a person’s symptoms and examining their skin.

Experts developed the Eczema Area and Severity Index (EASI) in 1998. This acts as a standardized tool to determine the severity of atopic dermatitis. Despite limitations surrounding its reliability, it is still a common diagnostic tool that doctors use.

Doctors will estimate the area of involvement across the head and neck, upper extremities, trunk, and lower extremities, which includes the legs.

They then assign it a score to indicate how much of the area the eczema is covering, ranging from:

  • 1 (1% to 9%)
  • 2 (10% to 29%)
  • 3 (30% to 49%)
  • 4 (50% to 69%)
  • 5 (70% to 89%)
  • 6 (90% to 100%)

Next, doctors assess each region for four signs:

  • skin reddening (erythema)
  • swelling (edema)
  • skin picking (excoriation)
  • lichenification

The final EASI score is the summation of the 4 regional scores, ranging from 0 to 72.

There are a range of treatments for eczema behind the knees, including:

Skin care

If the eczema is mild, people may only need to avoid triggers and look after the skin to help it heal.

This may involve:

  • avoiding triggers that make eczema flare up
  • maintaining a regular bathing and moisturizing routine to protect and strengthen the skin barrier
  • using emollients
  • using over-the-counter anti-itch creams

In more severe cases, wet wraps can help rehydrate and help make topical medications more effective. To prevent itching, people can wrap a wet dressing behind their knees, such as when sleeping.

Diet and lifestyle changes

For some, making diet or lifestyle changes helps with eczema. The following may also provide benefits:

Prescription treatment

If the above approaches are insufficient, doctors may prescribe a topical corticosteroid cream to use on the skin.

If this does not work, doctors may prescribe one of the following:

Doctors may also suggest diphenhydramine (Benadryl), an antihistamine, to help treat short-term sleep disturbances from itchiness.

Eczema is usually not serious or life threatening, but it can have significant effects on a person’s quality of life. It may disrupt:

  • sleep
  • the ability to concentrate at school or work
  • mental health

Itchy skin can also lead to infections if a person scratches the skin. A skin infection may appear similar to eczema itself, so individuals need to monitor for the following signs and seek medical attention if they develop:

Eczema often occurs in the creases of the skin, including the backs of the knees. Atopic dermatitis is the most common type, causing itchiness, dryness, and skin discoloration.

Both children and adults can develop eczema behind their knees or on other joint areas. Treatments include moisturizers, topical medications, and avoiding triggers. If the eczema is severe, a doctor may suggest wet wraps or prescription medications.