Eczema or Fungus: How to Differentiate?

Eczema is a chronic, non-contagious skin condition. It causes inflammation that results in redness, flaking, and itching. Eczema can affect all parts of the body and its intensity can vary, depending on periods of flare-ups and remission. The onset of eczema is often linked to a combination of genetic and external factors (contact with certain allergenic or irritating substances). The skin barrier is often compromised, allowing allergens to penetrate more easily and trigger disproportionate reactions.

Fungal infection, on the other hand, is a contagious skin disease. It is caused by fungi that are yeasts of the Candida type or dermatophytes. The proliferation of yeasts is favored by moisture, sweat, and also corticosteroids. Dermatophytes, on the other hand, feed on the keratin present on the skin, scalp, and nails. This type of fungus is the cause of scalp fungal infection, more commonly known as ringworm. The symptoms of ringworm are similar to those of scalp eczema . The fungal infection of the feet or hands, on the other hand, resembles dyshidrotic eczema.

The symptoms of eczema and fungal infections can appear quite similar, making it not always easy to distinguish between these two skin conditions. Indeed, the symptoms are alike: they involve itchy, scaly red patches on the skin or scalp. However, there are certain differences that can help to avoid confusion.

• The location of the plaques.

  Eczema typically appears on a specific area of the skin but can then spread to other parts of the body. Fungal infections, on the other hand, only infect one part of the body, often the nails or feet. However, it's worth noting that eczema can lead to a fungal infection and vice versa. Indeed, by activating the immune system, the fungi from the infection can trigger an eczematous response. Conversely, skin damaged by eczema is a favorable environment for a fungal infection.

• The shape of the plaques.

  The patches caused by a fungal infection have a very specific shape, rounded with a clear semicircular border. This is especially true for fungal infections caused by dermatophytes. Eczema patches do not necessarily have specific shapes.

• The intensity of itching.

  Unlike eczema, the itching caused by a fungal infection is moderate and tolerable. Therefore, intense itching sensations could be a sign that you are suffering from eczema.

• The treatment.

  Eczema and fungal infections are not targeted in the same way. For eczema, the solution involves daily application of emollients to combat the constant dryness of the skin (xerosis). This is accompanied by the use of topical corticosteroids during flare-ups. In the case of a fungal infection, topical corticosteroids do not work and can instead exacerbate the problem. The appropriate solution involves killing the parasitic fungi responsible for the disease. This is achieved through the targeted application of antifungal treatments.

Please note : this article only provides a few keys to differentiate between eczema and fungal infection. If you are in doubt, the first step is to consult a dermatologist.

• GOLDENBERG G. & al. Eczema. The Mount Sinai journal of medicine (2011).

• SAURAT J. H., LACHAPELLE J. M., LIPSKER D., THOMAS L. et BORRADORI L. Dermatologie et infections sexuellement transmissibles. Elsevier Masson (2017).