How can one determine whether it's seborrheic dermatitis or eczema?

Sometimes considered a form of eczema, seborrheic dermatitis, also known as seborrheic eczema, is a chronic inflammatory skin condition that primarily affects the areas rich in sebaceous glands, such as the scalp, face, chest, and skin fold regions. Common symptoms of seborrheic dermatitis include red and scaly patches, skin flaking, and sometimes itching, making it very similar to eczema. These signs can vary in intensity and appear in flare-ups, with periods of remission and relapse, just like in the case of eczema.

There are multiple but different causes for the development of eczema or seborrheic dermatitis. In the case of eczema, it is often a combination of genetic and external factors. The skin barrier is defective and allows allergens to pass through more easily, causing disproportionate reactions. Seborrheic dermatitis , on the other hand, is usually due to the proliferation of Malassezia type fungi or an overactivity of the sebaceous glands. Genetic predispositions are also sometimes responsible.

The symptoms of eczema and seborrheic dermatitis are similar, and it is not always easy to distinguish between these two skin conditions. Indeed, the skin lesions are quite alike, often presenting as red scaly patches on the skin or scalp. However, the causes and treatments for seborrheic dermatitis and eczema differ, which is why it is crucial not to confuse them.

• The visual differences between eczema and seborrheic dermatitis.

  At first glance, eczema lesions and seborrheic dermatitis appear identical. However, they exhibit some subtle differences. The red patches of eczema can appear swollen and scaly with some oozing areas. Seborrheic dermatitis, on the other hand, typically presents as red and scaly patches with a white or yellowish flaking. Moreover, if the scalp is affected, seborrheic dermatitis often results in dandruff, which are actually scales grouped into patches.

• The differences in location between eczema and seborrheic dermatitis.

  While eczema can affect almost all parts of the body (face, torso, legs, mouth, eyelids...), seborrheic dermatitis is generally more localised. In adults, it most often appears on the scalp and sometimes also affects the sides of the nose, eyebrows or the mid-chest area. In infants, seborrheic dermatitis always begins on the scalp, initially around the fontanelle before potentially spreading, sometimes to the ears or eyebrows. It can then affect the buttocks and folds.

  Note : this dual localisation (head and buttocks) is common in seborrheic dermatitis. It is much rarer for eczema to affect these two areas simultaneously.

• The perceptual differences between eczema and seborrheic dermatitis.

  If eczema flare-ups are always accompanied by itching of varying intensity, this is not necessarily the case with seborrheic dermatitis. Thus, constant feelings of itchiness could be an indication that you are suffering from eczema. Moreover, between flare-up periods, the skin of those affected by eczema remains very dry, this is referred to as xerosis. During remission periods of seborrheic dermatitis, the skin of affected individuals is also red and irritated but not consistently dry.

Please note : this article is purely informational and cannot under any circumstances replace a medical diagnosis. If you are uncertain whether you have eczema or seborrheic dermatitis, we advise you to consult a healthcare professional who can guide you.

• GOLDENBERG G. & al. Eczema. The Mount Sinai Journal of Medicine (2011).

• WIKRAMANAYAKE T. & al. Seborrheic dermatitis and dandruff: A comprehensive review. Journal of Clinical and Investigative Dermatology (2015).