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When is lichen planus nail not fungal? Patients who present with crumbly diseased looking finger and toenails can too easily be diagnosed with fungal nails (onychomycosis). The appearance is often similar. The nails can have thickening, splitting, lifting, thickening and subungual hyperkeratosis (hard skin under nail plate edge). Often patients have already been prescribed topical anti-fungal agents and have been using them religiously to nil effect.

So, what is nail lichen planus (LP)? Lichen planus is a benign dermatological skin condition affecting the skin and nails. It is thought to be an autoimmune issue.  An inflammatory mucocutaneous disorder. Stress, genetics and injury to the skin and nails have been cited as causative factors. In rare cases it has been suggested that maybe viruses or bacteria are triggers. Could Covid now be a factor? Anecdotally, more cases of fingernail plate disruption have been recently noted at Compleet Feet, in patients post covid. Lichen Planus affects fingernails more than toenails and more prevalent in women between 40 – 60. It is relatively uncommon with only about 10-15% of the general population formally diagnosed. Is this a true figure? How many cases haven’t been diagnosed?

Lichen Planus or Onychomycosis? A case of misdiagnosis?


Taken from the Journal of American Dermatology showing nail Lichen Planus

On examination of the presenting LP nails, they exhibit many signs of nail plate disease and irregularities:

  • Nail matrix involvement
  • Thickening
  • Longitudinal ridges
  • Nail plate thinning
  • Transverse ridges (trachyonychia)
  • Inflammation at base of nail plate
  • Cessation, retardation of nail plate growth
  • Pitting
  • Nail bed subungual skin thickening

Unlike fungal nails they are not discolored or have distinct yellow streaks or patches. Are less crumbly with no malodorous smell, but could easily be mistaken for being fungal, especially fingernails. It is estimated that 50% of diseased fingernails are caused by candida albicans leading to trichophyton  rubrum.  Unfortunately, a damaged lichen planus nail when compromised, can become fungal, hence the picture gets more complicated and trickier to diagnose.

The secret it seems is diagnose early. Look for the early signs of nail damage with longitudinal ridging, thinning and splitting. It is important to differentiate between LP and nail fungus.  Doing a 5-minute fungal nail test in clinic will help to diagnose the problem quickly. Compleet Feet offer this test in clinic.

As it is an inflammatory autoimmune issue, if it is diagnosed quickly then applying cortisone cream application may work, as will applying topical retinoids and urea-based products. The nails need to be reconditioned. Having a course of Lunula laser may help to accelerate healthy new nail growth. It boosts circulation and nutrition to the nail unit. For more chronic cases a course of oral steroids has been suggested to reduce the inflammation. Unfortunately, in chronic long-standing cases of nail LP, the nail plate can be irreversibly damaged, and in some cases do not grow back properly at all.

Speed is of the essence in treating nail LP and ensuring a patient gets a correct diagnosis. Too often it is a nail pathology that gets missed. More research needs to be done to understand the causes of LP and how to treat it.


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