Fungal nail infection
FUNGAL NAIL INFECTION
FUNGAL NAIL INFECTION DEFINITION
Nail fungus is a common condition that begins as a white or yellow spot under the tip of your fingernail or toenail. As the fungal infection goes deeper, nail fungus may cause your nail to discolor, thicken and crumble at the edge. It can affect several nails but usually not all of them.
If your condition is mild and not bothering you, you may not need treatment. If your nail fungus is painful and has caused thickened nails, self-care steps and medications may help. But even if treatment is successful, nail fungus often comes back.
Nail fungus is also called onychomycosis (on-ih-koh-my-KOH-sis) and tineaunguium. When fungus infects the areas between your toes and the skin of your feet, it’s called athlete’s foot (tineapedis).
FUNGAL NAIL INFECTION CAUSES
Nail fungal infections are caused by microscopic organisms called fungi that do not require sunlight to survive. Most commonly, a group of fungi called dermatophytes (such as Candida) is responsible for nail fungal infections. However, some yeasts and molds also cause these infections.
Though Trichophytonrubrum is the most common dermatophyte that causes nail fungal infections, Trichophytoninterdigitale, Epidermophytonfloccosum, Trichophytonviolaceum, Microsporumgypseum, Trichophytontonsurans, and Trichophytonsoudanensemay also cause the infections. Common mold causes include Neoscytalidium, Scopulariopsis, and Aspergillus.
Pathogens that cause nail fungus infection usually enter the skin through tiny cuts or small separations between the nail and nail bed. The fungi grow when the nail provides a suitably warm and moist environment.
FUNGAL NAIL INFECTION PATHOPHYSIOLOGY
The pathogenesis of onychomycosis depends on the clinical subtype. In distal lateral subungualonychomycosis, the most common form of onychomycosis, the fungus spreads from plantar skin and invades the nail bed via the hyponychium. Inflammation occurring in these areas of the nail apparatus causes the typical physical signs of distal lateral subungualonychomycosis. In contrast, white superficial onychomycosis is a rarer presentation caused by direct invasion of the surface of the nail plate. In proximal subungualonychomycosis, the least common subtype, fungi penetrate the nail matrix via the proximal nail fold and colonize the deep portion of proximal nail plate. Endonyxonychomycosis is a variant of distal lateral subungualonychomycosis in which the fungi infect the nail via the skin and directly invade the nail plate.
FUNGAL NAIL INFECTION SYMPTOMS
You may have nail fungus — also called onychomycosis (on-ih-koh-my-KOH-sis) — if one or more of your nails are:
- Brittle, crumbly or ragged
- Distorted in shape
- Dull, with no shine
- A dark color, caused by debris building up under your nail
Infected nails also may separate from the nail bed, a condition called onycholysis (on-ih-KOL-ih-sis). You may feel pain in your toes or fingertips and detect a slightly foul odor.
FUNGAL NAIL INFECTION DIAGNOSIS
In order to diagnose nail fungus infections, a doctor will usually examine debris that is scraped from underneath the nail. The nail scrapings will be used in tests such as a potassium hydroxide (KOH) smear or a fungal culture. The KOH test can be quickly performed, while the fungal culture can take weeks.
Physicians must be careful when diagnosing fungal infections of the nail because several other conditions can result in similar symptoms. These include psoriasis, lichen planus, contact dermatitis, trauma, nail bed tumor, eczema, and yellow nail syndrome., trauma, nail bed tumor, eczema, and yellow nail syndrome.
FUNGAL NAIL INFECTION TREATMENT
If self-care strategies and over-the-counter (nonprescription) products haven’t helped, your doctor may suggest a combination of prescription drugs and other approaches. But even if you find relief from your signs and symptoms, repeat infections are common.
- Oral antifungal drugs. Your doctor may prescribe an oral antifungal drug. Studies show the most effective treatments are terbinafine (Lamisil) and itraconazole (Sporanox). These drugs help a new nail grow free of infection, slowly replacing the infected part.
You typically take this type of drug for six to 12 weeks. But you won’t see the end result of treatment until the nail grows back completely. It may take four months or longer to eliminate an infection.
Treatment success rates with these drugs appear to be lower in adults over age 65. And treatment success seems to improve when you combine oral and topical antifungal therapies.
Oral antifungal drugs may cause side effects ranging from skin rash to liver damage. You may need occasional blood tests to check on how you’re doing with these types of drugs. Doctors may not recommend them for people with liver disease or congestive heart failure or those taking certain medications.
- Medicated nail polish. Your doctor may prescribe an antifungal nail polish called ciclopirox (Penlac). You paint it on your infected nails and surrounding skin once a day. After seven days, you wipe the piled-on layers clean with alcohol and begin fresh applications. You may need to use this type of nail polish daily for a year.
- Medicated nail cream. Your doctor may prescribe an antifungal cream, which you rub into your infected nails after soaking. These creams may work better if you first thin the nails. This helps the medication get through the hard nail surface to the underlying fungus.
To thin nails, you apply an over-the-counter (nonprescription) lotion containing urea. Or your doctor may thin the surface of the nail (debride) with a file or other tool.
Surgical or other procedures
- Nail removal. If your nail infection is severe or extremely painful, your doctor may suggest removing your nail. A new nail will usually grow in its place. But it will come in slowly and may take as long as a year to grow back completely. Sometimes surgery is used in combination with ciclopirox to treat the nail bed.
- Laser and light-based therapies. More study is needed, but these methods — alone or with medications — may help your nails improve. One study tested the effectiveness of carbon-dioxide laser therapy combined with antifungal nail cream. Most of the 24 people in the study benefited from the treatment.
Laser and light-based therapies are not available everywhere, are expensive, and often are not covered by insurance.