Assessing Dystrophic Nails: Finding the Cause

WHAT ARE FUNDAMENTALS FOR ASSESSMENT OF DYSTROPHIC NAILS?

When confronted with dystrophic nails, it is important to determine the cause. While onychomycosis is very often the cause, there as several nail conditions that present with nail dystrophy and can masquerade as onychomycosis.

Onychomycosis is marked classically by onycholysis, discoloration, thickening of the nail plate, subungual debris, and often discomfort. Thickened nails may become incurvated or ingrown, causing pain.

However, there are other potential causes of nail dystrophy. Improper biomechanics can lead to unnatural pressure on the nail, which causes the nail to become thickened and compacted. For example, in the case of a “hammertoe,” the nail may be positioned so that it faces downward and strikes the ground when the patient walks. This exposes the nail to unnatural ground reaction forces; Just as with other tissues, the nail thickens in response to repeated trauma (similar to a callus forming on soft tissue). In a similar way, the fifth toe is often subject to traumatic pressure from tight-fitting shoes, leading to thickening of the nail.

Nail dystrophy can also be a sign of other medical diagnoses, such as psoriatic nail disease or lichen planus.

Confirming the diagnosis of onychomycosis by documenting the presence of dermatophytes is recommended and easy to accomplish. Periodic acid–Schiff (PAS) staining can confirm the presence of dermatophytes within 24 hours, however, it cannot identify specific causative organisms. Potassium hydroxide (KOH) culture takes up to a month, but it allows for identification of a specific organism and thus can aid treatment selection.

WHAT IS THE IMPACT OF DYSTROPHIC NAILS ON PATIENTS?

The impact of dystrophic nails can be significant for patients. Both male and female patients report embarrassment over the condition. Male patients frequently mention that they try to avoid swimming pools and locker rooms to avoid exposing their nails. Women often mention that they can't or won't wear open-toe shoes. Some women report using bandages and other items to camouflage their toes.

Dystrophic nails can be associated with pain and therefore hindered ambulation. Hard, thickened nails may cause ulcerations on nearby digits. Onychomycotic nails may develop ulcerations under the nail bed.

Onychomycosis is also associated with interdigital tinea pedis and increased risk for diabetic ulcers. The temporal association between onychomycosis and tinea pedis is unclear; we do not know whether or how one may lead to the other.

ARE THERE EFFECTIVE OPTIONS TO REDUCE REINFECTION?

Clinically, we may see low rates of complete clearance and high rates of recurrence of onychomycosis. This could be associated with many factors, including the nature of therapy. However, we do know that patients often are re-exposed to dermatophytes.

Research has shown that laundering socks with a single wash cycle may not remove adherent dermatophytes. However, there are strategies to reduce re-exposure. While there are no clinical trials available, there is some evidence that copper-infused stockings are capable of reducing the bio-burden fungally. There is also evidence that an ultraviolet device called the SteriShoe can be used to reduce the fungal bio-burden of footwear.

Dr. Vlahovic is Associate Professor at Temple University School of Podiatric Medicine in Philadelphia, PA.