Fungal Skin Infections
Superficial fungal infections affecting the outer layer of skin, hair and nails, are common and generally mild. However, fungi can sometimes cause serious disease if the person is otherwise unwell or their immune system is suppressed.
Subcutaneous fungal infections affect deeper layers of skin, the dermis, subcutaneous tissue, and even bone.
Fungal infections of the nails are also known as dermatophytic onychomycosis, or tinea unguium.
They are caused by the same fungus that causes athletes foot – a common fungal infection that lives in the keratin on the outer layer of skin on the feet, especially between the toes. When this fungus spreads to the keratin in the nails it causes a fungal nail infection.
What Causes Fungal Skin Infections?
Fungal infections can be caused by a number of different factors which can be split into three categories; dermatophytes, yeasts, and moulds.
Dermatophytes cause most nail infections, yeasts and moulds tend to attack nails that are already damaged.
Fungus thrives in hot, moist environments, which means that fungal infections can often begin when feet are enclosed, hot, and sweaty for extended periods of time.
Athlete’s foot can also be caused by a fungal infection, but can have attributing factors such as bacterial infection, mould infection, soft corn, injury or existing skin conditions. Athletes foot can be spread from person to person through fungal spores left on surfaces.
Who is at risk of Fungal Skin Infections?
Fungal nail infections are more likely to affect the elderly, or those with weakened immune systems. They are also more likely to affect those with diabetes. They are rare in children.
Athletes foot is more likely to affect those who participate in sport, or those with physical jobs, due to feet becoming sweaty in enclosed footwear.
What are the symptoms of Fungal Skin Infections?
In the case of nail infections, (onychomycosis), the first noticeable symptom may be the nail becoming so thick that it causes discomfort when wearing shoes. Affected nails are difficult to cut back and therefore may damage any tights or socks worn.
The most commonly affected areas are the little and big toes, although other toes and fingernails can also be affected.
Usually the fungus spreads from the edges, down to the cuticle turning the affected areas a white, yellowish colour, and making the nail appear thick and crumbly. A white/yellow streak may appear on one side of the nail.
If the infection is caused by the candida strain of fungus, the infection starts at the the cuticle making the nail fold swollen and red. The nail may lift up at the edge, and white, yellow, green and black marks may appear.
In the case of athletes foot, when the surrounding skin is also affected by a fungal infection, this will usually appear as moist, soft skin that it easy to peel off. It usually appears between the toe clefts of the fourth and fifth toes, and can appear white due to peeling. It can cause itchiness and irritation, but is generally painless.
Images of Fungal Skin Infections
These images are kindly provided by DermNetNZ.org for non-commercial use, for the purpose of education and information. The images have not been modified and DermNetNZ do not endorse The London Skin and Hair Clinic. You can find a copy of the license at http://creativecommons.org/licenses/by-nc-nd/3.0/nz/.
How does a dermatologist diagnose Fungal Skin Infections?
How does a dermatologist treat Fungal Skin Infections?
A Dermatologist will start treatment based on physical examination so that by the time a laboratory result is back, the condition may be improved. In the case of athletes foot, the treatment would usually be topical treatment, many of which can be purchased without a prescription. These come in varying forms of gels, sprays, lotions, or powders. Treatment usually lasts 1 to 6 weeks.
Not all fungal nail infections need treating. If they are not causing physical or emotional discomfort then many people choose not to treat them at all, although care must be taken to ensure the fungus doesn’t spread to other part of the body, or other people.
If the infection is causing distress, the first option for nail infections affecting less than half of the nail, would be topical antifungal medications, usually combined with oral antifungal medication. This can take several months, and cause a variety of uncomfortable side effects.
Laser treatment is sometimes suggested for treating nail infections however the clinical results have not been compelling to support this form of treatment.