Toenail fungus (onychomycosis) is a persistent infection that causes the nail to become discolored, thickened, and brittle. It is caused by fungi, often dermatophytes, which thrive in warm, moist environments. Since the fungus is embedded within the nail structure, treatment can be lengthy and often requires professional intervention. Medicare coverage for this treatment is highly conditional and depends on the patient’s overall health and the infection’s severity.
The General Rule: Routine Foot Care Exclusion
Medicare generally excludes services considered routine foot care. The Social Security Act and guidance from the Centers for Medicare & Medicaid Services (CMS) define routine services as hygienic or palliative maintenance. This includes trimming, cutting, clipping, or debriding nails for an otherwise healthy individual. Services performed simply to maintain the nail’s appearance or prevent minor discomfort are not covered benefits.
This exclusion applies even if the toenail is thickened or discolored due to fungus, provided the patient does not have an underlying systemic disease. Medicare assumes the patient or a caregiver can perform this type of maintenance themselves. In the absence of a serious complicating factor, a podiatrist visit for uncomplicated fungal nail trimming is considered a non-covered service.
For coverage to be considered, the service must transition from a routine maintenance procedure to a medically necessary intervention. This distinction is the basis for nearly all exceptions to the rule. The healthcare provider must document the medical necessity to justify coverage.
When Treatment Becomes Medically Necessary
Treatment becomes medically necessary when the fungal condition poses a direct threat to the patient’s health due to a systemic disease. This exception applies primarily to patients with systemic conditions causing severe circulatory issues or nerve damage in the legs and feet. Examples include severe diabetes, peripheral vascular disease, or certain neurological conditions.
For these at-risk patients, a minor injury from a thickened, fungal nail or an accidental nick during trimming could lead to a non-healing foot ulcer, severe infection, or even amputation. Medicare will cover the debridement—the reduction of the nail’s thickness and length—if it is required to prevent a more serious complication. Coverage for this type of debridement is generally limited to once every 61 days.
Medical necessity hinges on documentation proving the infection is symptomatic (e.g., causing pain that limits walking) or that the patient has a qualifying systemic condition. Diabetes alone is insufficient; the patient must show evidence of peripheral neuropathy or poor circulation that makes professional foot care a safety necessity. The patient must also be under the active care of a medical doctor or osteopath for the systemic condition within the six months prior to the foot care service.
Coverage Based on Treatment Method (Part B and Part D)
Once the medical necessity for treating onychomycosis is clearly established, coverage depends on the type of treatment used. Medical and surgical services, such as a podiatrist’s visit, diagnosis, and the debridement procedure, fall under Medicare Part B. Part B covers medically necessary outpatient services. Patients are typically responsible for 20% of the Medicare-approved amount after meeting the annual Part B deductible.
If the treatment plan involves prescription oral antifungal medications, such as Terbinafine, coverage is handled separately under Medicare Part D. Part D is the prescription drug benefit and requires enrollment in a stand-alone plan or a Medicare Advantage plan that includes drug coverage. The cost to the patient for these medications will vary significantly based on the specific Part D plan’s formulary, tier structure, and whether the annual deductible has been met.
Non-traditional therapies, such as laser treatment for toenail fungus, are generally not covered by either Part B or Part D. Most Medicare carriers consider laser therapy to be cosmetic, experimental, or investigational, as there is no national coverage determination supporting its efficacy. Patients who opt for laser treatment should expect to pay the full cost out-of-pocket.