Given the common presentation of onychodystrophy, physicians should have a firm grasp of common presentations of conditions like onychomycosis, trachyonychia and psoriasis. Accordingly, this author reviews keys to effective diagnosis and pertinent treatment considerations.
Nail cosmesis and discomfort are the main motivators for most of our patients to schedule a podiatric consultation. During that patient visit, it is important for the podiatric practitioner to delve into the cause of the problematic nail change, known as onychodystrophy.
Onychodystrophy, which is any alteration of nail morphology, encompasses a wide spectrum of nail disorders. Caused by either exogenous or endogenous factors, nail dystrophy may manifest as a misshapen, damaged, infected or discolored nail unit that may affect the toenails, fingernails or both.
Among the exogenous factors causing onychodystrophy are trauma, wetting/drying, chemicals and infection (dermatophytes, yeast or bacteria). The endogenous factors include decreased nail formation secondary to radiation, toxins, decreased oxygenation, decreased vascularization, metabolic/endocrine disorders, inflammatory disorders and neoplasms.
When describing these affected nails, clinicians commonly use morphologic terms such as onycholysis, onychauxis and onychorrhexis. Onycholysis describes the separation of the nail plate from the nail bed. This condition may be caused by exogenous trauma but also may be caused by a systemic disorder like psoriasis. The pocket created also forms a pathway for dermatophytes to infect the nail bed. Onychauxis is thickening of the nail unit that occurs in both onychomycosis and psoriasis. Onychorrhexis presents as nail plate ridges parallel to the lateral nail fold. This may arise as a sign of normal aging or as the manifestation of underlying diseases such as lichen planus and psoriasis.
An Overview Of The Various Presentations Of Onychomycosis
The most common type of nail dystrophy we see as podiatric practitioners is onychomycosis, which represents about half of the nail pathologies.1 However, the physician should be aware of the numerous other pathologies that may mimic dermatophyte infection of the nail such as psoriasis, lichen planus, trachyonychia and trauma.
Onychomycosis or tinea unguium is caused by invasion of the nail unit by dermatophytes, non-dermatophyte molds and/or Candida albicans. Clinicians generally describe onychomycotic nails as onycholytic, discolored and/or hyperkeratotic with subungual debris. One may see concomitant tinea pedis or tinea cruris in patients with onychomycosis.
The most common form of onychomycosis on the toenails is distal lateral subungual onychomycosis caused by Trichophyton rubrum. Clinically, it may be difficult to distinguish onychomycosis from other existing nail pathologies. KOH preparation, periodic acid Schiff (PAS) staining and fungal culture can aid in determining the presence of a dermatophyte-caused infection.
There are several types of onychomycosis that one can differentiate by the initial site of involvement and pathophysiology. The classification of onychomycosis is as follows.2
Distal (or distal lateral) subungual onychomycosis. This is the most common type in adults and children. It presents as onycholysis with discoloration, subungual debris and hyperkeratosis. Concurrent tinea pedis often occurs interdigitally or plantarly on the foot. Trichophyton rubrum is the most common pathogen.
Proximal subungual onychomycosis. It is common to see this in immunocompromised patients as a leukonychia or white discoloration of the proximal nail plate. One generally does not see distal subungual debris in this manifestation. Trichophyton rubrum and non-dermatophyte molds are the common pathogens in this nail disease.
Candidal onychomycosis. Onychomycosis caused by Candida most often occurs in patients who have chronic mucocutaneous candidiasis. The nail can present with onycholysis and paronychia.
Superficial white onychomycosis. The white powdery material one sees with this type of onychomycosis is present on the dorsal aspect of the nail plate. Clinicians can scrape this off with a scalpel blade. One sees this condition in patients in tropical climates and it is typically caused by Trichophyton mentagrophytes or non-dermatophyte molds. Clinicians may mistakenly identify proximal subungual onychomycosis as superficial white onychomycosis in very young children due to their thin nail plates.
Treatment for onychomycosis includes targeting the causative organism with either oral terbinafine (Lamisil, Novartis), oral itraconazole (Sporanox, Janssen Pharmaceuticals) in pulsed doses, oral fluconazole (Diflucan, Pfizer) in once-a-week dosages, oral griseofulvin (Grifulvin V, OrthoNeutrogena) or topical ciclopirox lacquer (Penlac, Sanofi-Aventis) among many other over-the-counter and compounded remedies.
It is also standard to employ mechanical debridement to debulk the nail unit to allow better penetration of topical medications and increased comfort in shoes. Clinicians may also use topical urea preparations to soften and smooth the nail plate, and apply a laser such as the 1064 nm YAG to theoretically create an inhospitable environment for the dermatophyte.
What To Look For With Nail Psoriasis
Psoriasis can affect the skin, nails and joints. Classically, psoriatic nail disease consists of: onycholysis; salmon (oil) spots (discolored areas that represent nail bed psoriasis); an irregular pitting pattern; and onychauxis. The Koebner phenomenon, or the appearance of lesions at the site of injury, can also occur in the nails and may manifest in an asymmetrical presentation. If a patient presents with an onychomycosis-like nail involvement and has failed oral antifungals, one should consider a diagnosis of psoriatic nail disease.
Also, if psoriatic plaques and nail dystrophy are present, they do not automatically lead to a diagnosis of psoriatic nail disease.1 This is why culture and biopsy with negative PAS stain are essential to achieve the correct diagnosis. In addition to the nail changes, periungual erythema may be present. Patients may also present with the arthritic component of psoriasis, which may manifest in dactylitis of the digits (sausage toes), enthesitis of the Achilles tendon and distal interphalangeal joint involvement.
Management of nail psoriasis involves reducing the inflammatory response. The most common treatments include: injection of a corticosteroid (such as Kenalog, Bristol-Myers Squibb) into the nail matrix; the use of topical calcitriol (Rocaltrol, Roche USA), calcipotriene (Dovonex, Warner Chilcott) or tazarotene (Tazorac, Allergan); oral acitretin (Soriatane, Stiefel Laboratories); or the use of systemic infliximab (Humira, Abbott Laboratories).
Pertinent Insights On Lichen Planus Of The Nail
Lichen planus is an idiopathic T cell-mediated inflammatory condition, which affects the skin, hair, nails and mucous membranes. This condition more commonly affects fingernails but in my practice, I have found this toenail disease to be more common than the literature describes.1
Several nails are generally involved in presentations of lichen planus. The nails become thin, rough (trachyonychia), ridged longitudinally (onychorrhexis), fissured and can develop a dorsal wing formation of the proximal nail fold (or pterygium formation) over the nail plate. If the matrix damage from lichen planus goes unaddressed, these nail findings become permanent scarred reminders of the skin disease. Clinicians may address this by injecting steroids into the nail matrix.
Understanding The Presentation And Treatment Of Trachyonychia
Trachyonychia has also been referred to as “20 nail dystrophy” or rough nails. This is a benign condition that primarily affects children. One may see this in association with lichen planus, psoriasis, alopecia areata and atopic dermatitis. Clinicians may misdiagnose this condition as onychomycosis if they do not elucidate the underlying inflammatory condition causing trachyonychia.
Treatment includes filing or buffing of the nails, oral biotin supplements, urea nail preparations and triamcinolone injections into the nail matrix. Trachyonychia may also spontaneously resolve with time.
What You Should Know About Trauma-Induced Nail Dystrophy
During a pedicure, the process of manipulating the cuticle may lead to Beau’s lines or depressions of the nail plate that are parallel to the proximal nail fold. Also, scraping of the hyponychium can lead to onycholysis, which provides a pocket for dermatophyte infection to take hold.
Often due to shoegear, the fifth toenail becomes dystrophic and thickened.3 Patients and practitioners alike will confuse this with onychomycosis. If one sees this with concomitant onychomycosis and employs systemic treatment, he or she should discuss with the patient the possibility that the fifth toenail may not respond to oral antifungals. The underlying cause of the dystrophy can be biomechanical (an adductovarus fifth toe) or tight fitting shoes. A Lister’s corn or focal hyperkeratotic lesion that may appear to the patient as a “split nail” lateral to the nail plate may also be present.
Onychauxis, onycholysis and discoloration secondary to the trauma of a severely contracted hammertoe may frustrate the patient who is pursuing antifungal therapy and questioning why a treatment regimen is not successful. In these cases, it is imperative to educate the patient about the biomechanical cause of the nail thickening and the treatment options. These range from purchasing a shoe with a deeper toe box to decrease pressure to surgical management of the digital deformity if warranted.
Iatrogenically caused onychodystrophy can arise following a biopsy of the proximal nail matrix.4 The practitioner should inform the patient during the informed consent process that this can occur. One can prevent this by procuring the biopsy from the distal nail matrix if possible.
A Closer Look At Emerging Treatment Options
Treatment of the underlying condition or infection present in onychodystrophy may be a slow and frustrating process to both the patient and practitioner. In addition to the various therapies I have outlined above, clinicians should consider other therapies and devices that will adhere to the nail plate, provide mechanical support and be easy to use.
Two of the newest medical devices available for the treatment of onychodystrophy are hydroxypropyl chitosan (Genadur™, Medimetriks) and poly-ureaurethane 16% (Nuvail™, Innocutis). These are non-drug lacquers that patients would apply topically to the nail at bedtime.
Genadur is indicated to “protect damaged nails from the effects of moisture, friction or shear” in order to relieve the symptoms of nail dystrophy.5 It is a hydrosoluble compound that patients should apply after washing and drying their nails. Studies on psoriatic nails have shown that it has an improvement in nail fragility, a reduction in splitting and a 63 percent reduction in onycholysis.6
Nuvail is a waterproof and flexible film that forms to the nail contour to provide protection from direct abrasion and optimal moisture balance to protect the nail from the effects of moisture.7 Nasir and colleagues followed 53 patients with nail dystrophy who used Nuvail nightly.8 In their clinical assessment, which evaluated color, onycholysis and subungual hyperkeratosis, the researchers noted a 60 percent improvement after six months of use.
In addition, if cosmesis is a concern for the patient, Keryflex™ (Pod-Advance) nail resin may camouflage and protect the nail unit. Physicians have used Keryflex to cover nail fungus and various other nail dystrophies whether or not the patient is receiving systemic treatment for the underlying condition. While Keryflex has many uses, physicians have used the modality following laser use for onychomycosis and in covering a nail that has become dystrophic following surgery for a paronychia.
Biotin, an oral option for brittle nails, benefits dystrophic nails approximately two to three months after patients start using the supplement.9 Although there is no protocol on optimal duration of use, biotin supplementation should continue as long as there is clinical improvement.
In review, the treatment of nail dystrophy should first involve elucidating the cause. Is it caused by an infection, an underlying systemic cause or trauma? It should be clear that not all nail dystrophies are onychomycosis. One should pursue a fungal culture/mycological staining prior to treatment to confirm the clinical diagnosis. Ultimately, one should tailor treatment to the nail disorder present. The newest treatments for onychodystrophy include application of a non-drug topical, which is meant to provide support and protect the nail from further damage.
Dr. Vlahovic is an Associate Professor and J. Stanley and Pearl Landau Fellow at the Temple University School of Podiatric Medicine.
1. Allevato MAJ. Diseases mimicking onychomycosis. Clin Dermatol. 2010; 28(2):
2. Vlahovic TC, Schleicher SM. Nail Disorders. In: Skin Disease of the Lower Extremities: A Photographic Guide, Ch. 1, HMP Communications, Malvern, PA, 2012, pp. 19-20.
3. Bodman MA. Nail dystrophies. Clin Podiatr Med Surg. 2004; 21(4):663-687.
4. Nouri K. Complications in Nail Surgery. In: Complications in Dermatologic Surgery, Mosby, New York, 2008, p. 144.
5. Genadur PI, Medimetriks. Available at http://medimetriks.com/PIs/Genadur_PI.pdf .
6. Cantoresi F, Sorgi P, Arcese A, et al. Improvement of psoriatic onychodystrophy by a water-soluble nail lacquer. J Eur Acad Dermatol Venereol. 2009; 23(7):832-4.
7. Nuvail PI, Innocutis. Available at http://innocutis.com/wp-content/uploads/2012/06/nuvail-pi_0612.pdf .
8. Nasir A, Goldstein B, van Cleff M, and Swick L. Clinical evaluation of safety and efficacy of a new topical treatment for onychomycosis. J Drugs Dermatol. 2011; 10(10):1186-1191.
9. Scheinfeld N, Dahdah MJ, and Scher R. Vitamins and minerals: their role in nail health and disease. J Drugs Dermatol. 2007; 6(8):782-787.
For further reading, see “Roundtable Insights On Treating Onychomycosis” in the May 2011 issue of Podiatry Today.
Dr. Vlahovic pens a monthly blog for Podiatry Today. To access it, visit http://tinyurl.com/cb9shvn .