How To Treat Dystrophic Nails
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.