Types of Fungal Nail Infection
Types of Fungal Nail Infection
There are four major types of fungal nail infection . They are named for the area where the fungal infection starts. Dermatophytes cause almost all fungal nail infections.
- Distal subungual onychomycosis (DSO) is the most common type of fungal nail infection. It is caused by the same fungi that cause most cases of athlete's foot (dermatophytes). DSO infects the skin under the end of the nail (nail bed) and in the nail. The infection starts at the end of the nail bed, and part of the nail often turns yellow or white. Pieces of skin and nail fragments (debris) build up under the nail. As the condition gets worse, the nail may crumble and split, and it may separate from the skin. A thickened nail and a large amount of debris under the nail may cause discomfort when wearing shoes. DSO can be a lifelong infection and hard to treat. Shoes that fit poorly may make the infection worse or, in some cases, even cause the infection.
- White superficial onychomycosis (WSO), the second most common type of fungal nail infection. It can be easily treated. WSO affects the top layer of the nail, first forming white spots on the nail surface. Eventually the entire surface of the nail becomes covered with a crumbly, chalky powder. The nail does not thicken and does not separate from the skin.
- Candida onychomycosis, or yeast infection of the nail, is uncommon but can affect the nail and the skin bordering the nail (nail folds). This type of fungal infection is more common in fingernails than toenails. It may involve all of the nails at the same time and can cause the nail to separate from the nail bed. It invades weakened areas of the nail, which may become discoloured white, green, or brownish, with an odd shape. The nail may look thicker than normal, and there may be signs of infection (reddened, swollen, tender, or warm) in the skin next to the nail (nail fold). Unlike the other types of fungal nail infections, the infection may be painful.
- Proximal subungual onychomycosis (PSO) is caused by dermatophytes. It is more common in people infected with the human immunodeficiency virus (HIV) . PSO infects the base of the nail (skin at the nail fold), often thickening the skin, which can separate from the nail. The base of the nail may appear white, and the nail opaque. The skin on top of the foot may become infected.
Primary Medical Reviewer Patrice Burgess, MD - Family Medicine
Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Current as ofFebruary 20, 2015
Public Health Alerts
Public health alerts include information about outbreaks, advisories and product recalls. Click on the links below to read the most recent alerts, or visit our Public Health Alerts web page.
Want More Information?
HealthLink BC, your provincial health line, is as close as your phone or the web any time of the day or night, every day of the year.
Call 8-1-1 toll-free in B.C. or for deaf and hearing-impaired, call 7-1-1.
You can speak with a health service representative, who can also connect you with a:
- registered nurse any time, every day of the year;
- registered dietitian from 9am to 5pm, Monday to Friday;
- pharmacist from 5pm to 9am, every day of the year.
Translation services are available in more than 130 languages.
FIND Services and Resources
If you are looking for health services in your community, you can use our directory to FIND hospitals, clinics, and other resources.
To learn more about Healthwise, visit Healthwise.org.
© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Is it an emergency?
If you or someone in your care has chest pains, difficulty breathing, or severe bleeding, it could be life-threatening. Call 9-1-1 or the local emergency number immediately. If you are concerned about a possible poisoning or exposure to a toxic substance, call Poison Control now at 1-800-567-8911.