Ugly toenails: There’s a fungus among us
By Neil Alan Fenske, MD
Tampa Tribune correspondence
Hot weather is still here. Grabbing the sunscreen, wide-brimmed hat and umbrella, you’re ready for a day at the beach. Much to your chagrin, as you slip into your flip flops, you notice that your toenails are thick, discolored, loose and crumbling. Moreover, the bottoms of your feet are pink, dry and scaly. Maybe you’ll stay home instead.
The unsightly condition known as tinea pedis, or athlete’s foot, is a common fungal infection primarily affecting the skin of the feet. It may coexist with nail fungus, known as onychomycosis, and be caused by the same type of microorganism (Trichophyton rubrum). Since this contagious fungus thrives in warm moist places, like locker rooms, you might avoid infection in the first place by keeping your feet dry and never walking barefoot in public places.
Fungal foot and toenail infections tend to increase as we get older, in part because of more years of exposure to the fungal spores and our diminishing ability to fight off infection as we age. Typically, the infection starts on the skin of the feet and insidiously works its way under the distal edge of your toenail resulting in a yellowish discoloration. Eventually, the entire nail plate is destroyed as the fungus spreads through the nail to the cuticle. This fungus typically causes minimal itching so patients are often unaware of the infection until it begins to destroy their nails. When just the feet are affected, many patients think they simply have dry skin.
The clue this is a fungal infection is that the scaling has a proclivity for creases and the affected areas are pink. The infection often involves the bottom and sides of the feet in a so-called “moccasin” distribution.
Treating fungal infection is important for more than cosmetic purposes. The condition will worsen over time. Microscopic cracks in the skin caused by the infection and trauma to surrounding toes by the abnormal nails create a “portal of entry” for infection by other more serious organisms such as staph and strep. For those with weakened immune systems (patients undergoing chemotherapy, those with HIV infection or poorly controlled diabetes), these secondary bacterial infections may be very serious. With antibiotic-resistant bacteria (MRSA) now more prevalent in the community, this becomes a bigger problem, even for healthy people.
Treatment is a challenge, especially for the nails. While many effective topical agents are available over the counter for treating the skin, they are generally ineffective for nails. Moreover, toenail fungus frequently recurs. Nails generally require prescription antifungal pills taken daily along with the use of topical agents during and after treatment to prevent recurrence. Trimming away the damaged portion of the nail may also help.
Older drugs such as griseofulvin had to be taken until the nails were completely clear – as much as 18 months or more for older people with severe fungal infections! This increased the risk of adverse effects. Newer antifungal medicines (terbinafine and itraconazole) deposit in the nail plate and continue working months after the drug is discontinued. They are much safer to administer since treatment typically requires only three to four months. While relatively safe, antifungals can be hard on your liver, interact with other drugs and cause skin rash. Close monitoring by your dermatologist can help minimize the severity of side effects considerably.
With proper treatment of foot and toenail fungus, there’s no reason not to enjoy your day at the beach.
Dr. Fenske is professor and chair of the Department of Dermatology and Cutaneous Surgery at USF Health.