What are the differences between nappy rash and a fungal infection?

Fungal infection is a contagious skin disease caused by fungi. This can be yeast of the type Candida or dermatophytes, microorganisms that feed on the keratin found on the skin, scalp, and nails. The proliferation of these fungi is particularly encouraged by moisture, perspiration, and also corticosteroids. Fungal infections can affect any part of the body, but they are frequently found on the feet and buttocks, areas prone to friction and maceration.

The nappy rash is a common skin inflammation in infants and young children , characterised by redness and irritation in the nappy area. It primarily results from prolonged skin contact with moisture, particularly urine and faeces, which disrupts the skin barrier and promotes the onset of irritations. The friction of nappies, inappropriate hygiene, or the use of irritating products can also exacerbate the situation. In some cases, a bacterial or fungal infection, such as an overgrowth of Candida albicans, can occur and complicate the nappy rash. It is particularly in this circumstance that it can become difficult to distinguish a nappy rash from a fungal infection.

The symptoms of a nappy rash and a fungal infection are quite similar, making their distinction challenging.

However, certain elements can provide clues and help differentiate between a fungal infection and nappy rash. Firstly, in the presence of nappy rash, the skin is generally smooth and red, without the formation of raised lesions. When this condition is exacerbated by a bacterial or fungal infection, symptoms can progress and blisters, sometimes filled with pus, can develop. A fungal infection is immediately characterised by marked lesions, resembling red patches surrounded by a clear border, often lighter in the centre and darker at the edge. Furthermore, areas affected by a fungal infection are often more painful and itchier than those due to nappy rash. Additionally, in some cases, the fungal infection is accompanied by cracks and scabs.

Another aspect to monitor in order to determine whether one is dealing with a fungal infection or nappy rash: the circumstances of onset. Indeed, a fungal infection is solely caused by a fungal invasion, whereas the development of nappy rash is linked to friction and prolonged skin contact with moisture. Thus, redness appearing without the wearing of nappies or ill-fitting underwear should suggest a fungal infection, not nappy rash. Lastly, nappy rash only develops in the buttocks, groin and thigh areas, which is not the case for fungal infections that can appear on the hands or feet.

Unlike the nappy rash, which usually disappears quickly with some hygiene rules and, in some cases, medication, a fungal infection requires the use of antifungal agents to eradicate the infection.

Please note : This article only provides a few key points to distinguish between nappy rash and a fungal infection. If you are uncertain, the first course of action should be to consult a healthcare professional.

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• ROSA MARIA P. O. & al. Superficial Mycoses Associated with Diaper Dermatitis. Mycopathologia (2016).

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