Is eczema on flexor or extensor surfaces?

What do flexor and extensor mean?

Flexural areas are the folds where a joint bends, such as the inside of the elbow and behind the knee. Extensor areas are the opposite surfaces, such as the outer elbow and front of the knee. Flexural and extensor describe locations, so an elbow gets two technical names without doing any extra work.34

The same condition is called atopic eczema and atopic dermatitis, so the vocabulary has already doubled before the appointment starts. Eczema is a broader term for a group of inflammatory skin conditions; the age related flexural and extensor pattern discussed here refers specifically to atopic dermatitis, the most common type.35

Where does eczema appear at different ages?

These are common patterns, not fixed age boundaries. Infant eczema can involve skin creases as well as extensor limbs, and its distribution changes as children develop. A rash outside the elbow or knee creases does not automatically rule out atopic eczema.6

Does skin tone change the pattern?

In older children with darker skin tones, patches tend to appear on the fronts of the knees, outer elbows and backs of the hands rather than only in the creases. Children with brown or black skin are also more likely to have patches on the trunk. Eczema can look brown, purple or gray rather than red, and small, rough bumps are more common in darker skin tones. Looking only for a red rash in a fold can miss the pattern.2

Can eczema stay on the outer elbows or knees?

Yes. Atopic eczema on the extensor knees is sometimes called a reverse pattern. These patches can have scratch marks, thickened skin and darker pigmentation. Thickening from repeated rubbing or scratching is called lichenification. Eczema can also affect the outer elbows, so extensor involvement is not limited to infancy.14

Can location tell you whether a rash is eczema?

Location is a clue, not a diagnosis. A clinician also considers itching, dry skin, when symptoms began, previous flares and personal or family history. Psoriasis and contact dermatitis are among the conditions that can resemble atopic eczema. Arrange an assessment if the diagnosis is uncertain, treatment is not controlling the rash, or itching is disrupting sleep or daily activities.17

What should you do about the patches?

For diagnosed atopic eczema, apply a fragrance free moisturizing cream or ointment at least twice daily, particularly after bathing, and continue moisturizing when the skin is clear. Avoid known irritants and use prescribed creams as directed. Steroid strength depends on severity and the body area, not simply whether the rash is flexural or extensor. Treatment can ease itching before the rash fades; visible improvement can take days to weeks.37

Contact a clinician for yellow or golden crusts, pus, swelling or increasing pain. Seek urgent same day assessment for rapidly worsening painful eczema with clustered blisters or small punched out sores, especially with fever or unusual tiredness. These can signal eczema herpeticum, a serious viral infection.237