Eczema or fungal infection: how to tell the difference?

The eczema is a chronic noncontagious skin disease. It causes inflammation that leads to redness, scaling, and itching. Eczema can affect any part of the body and vary in severity, with flare-ups and remissions. The onset of eczema is most often linked to a combination of genetic factors—namely a defective skin barrier and an inappropriate immune response—and environmental factors, such as exposure to allergens or irritants. This skin barrier disruption facilitates the penetration of foreign substances that trigger exaggerated and chronic inflammatory reactions.

Mycosis is a contagious skin condition caused by fungi, mainly yeasts of the genus Candida or dermatophytes. Yeast proliferation is favored by a warm, humid environment, sweating, or prolonged corticosteroid use. Dermatophytes, in turn, feed on the keratin present in the skin, scalp, and nails. It is this type of fungus that causes scalp mycosis, more commonly known as ringworm. Its symptoms are similar to those of eczema of the scalp, with red, circular lesions accompanied by itching. Similarly, fungal infections of the hands or feet may present vesicles or scaling that resemble those of dyshidrotic eczema, making diagnosis challenging.

Eczema and fungal infection symptoms can resemble each other. In both cases, one observes red, scaly, and pruritic patches that can affect the skin or scalp. However, certain clinical signs enable differentiation. Recognizing these features helps determine whether a fungal infection or eczema is present.

• Localization of plaques.

  Eczema often manifests in specific areas, such as the creases of the elbows, behind the knees, the face, or the scalp, but it can then spread to other parts of the body depending on disease progression. Mycosis, by contrast, generally remains confined to a specific area, most often the feet, the nails (onychomycosis) or the scalp (tinea). It should be noted that the two conditions can overlap: a mycosis can trigger an eczematous reaction through immune system activation, while skin weakened by eczema becomes a favorable environment for fungal proliferation.

• Shape of the plates.

  The patches associated with a fungal infection have a distinctive shape—round or oval with a sharp, sometimes raised border—creating the characteristic arc-like appearance of dermatophytes. Some fungal lesions may also display small vesicles or scales at the center of the lesion. Eczema patches, by contrast, have irregular, diffuse edges and may exhibit widespread redness, crusting, or fissures depending on the severity of the inflammation.

• Intensity of itching.

  Pruritus is a symptom of eczema and fungal infection, but its intensity varies. In eczema, the itching is often severe and persistent, sometimes waking you at night. In the case of a fungal infection, pruritus is generally moderate and tolerable. Thus, intense itching can be a sign that you are suffering from eczema.

• Evolution over time.

  Eczema follows a chronic course, with flare-ups and remission periods, whereas a fungal infection progresses more continuously if left untreated. The persistence of plaques despite the application of emollient therapies and corticosteroid-type anti-inflammatory agents corticosteroids, may point toward a fungal infection rather than eczema.

Eczema and fungal infection: two conditions to distinguish, as they require different treatment approaches.

Although their symptoms may appear similar, eczema and mycosis are based on different biological mechanisms, requiring distinct therapeutic approaches. Eczema results from non-infectious skin inflammation, often associated with a disrupted skin barrier and immune hyperreactivity. Management therefore aims to restore the skin barrier function with daily emollient applications to limit dryness (xerosis) and to calm inflammation during flare-ups using corticosteroids.

Mycosis, by contrast, is a fungal infection. In this case, corticosteroids are contraindicated: they can weaken local defenses and promote the progression of the infection. Treatment therefore relies on antifungal agents, such as fluconazole or posaconazole, applied topically or sometimes prescribed orally depending on the extent of the mycosis.

Note : This article provides only a few key points to differentiate between eczema and a fungal infection. If you have any doubts, your first instinct should be to consult a dermatologist.

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