Treating Dystrophic Hallux Nails In A Six-Year-Old Boy
A 6-year-old male who likes to play sports presents with painful great toenails that have been present in the current condition since birth. They are painful in various shoes. His mother has taken him to other physicians who stated that the condition is not caused by nail fungus but they have offered no other solution. The patient has no pertinent past medical or birth history, no medications and no history of this on any other digit.
Upon examination, his bilateral hallux toenails are discolored, thickened, rough in appearance and deviated laterally. No lesions are present on the other toenails or fingernails.
Key Questions To Consider
1. What are the main characteristics of this condition?
2. What is the most likely diagnosis?
3. What is your differential diagnosis?
4. What is the characteristic nail deformity in this condition?
5. What is the treatment?
Answering The Key Diagnostic Questions
1. The characteristics most associated with this nail condition are the lateral deviation of the nail plate with transverse ridging of the hallux toenail.
2. The most likely diagnosis is congenital malalignment of the great toenail.
3. Differential diagnoses include onychomycosis, onychogryphosis or paronychia.
4. The characteristic nail deformity in this condition is the dystrophy of the nail plate with a lateral deviation of the nail in comparison to the longitudinal axis of the proximal phalanx.
5. Treatment ranges from conservative care to a surgical rotation of the misaligned matrix.
What You Should Know About Congenital Malalignment Of The Great Toenails
Samman and colleagues first described congenital malalignment of the great toenails in 1978 as a great toenail “dystrophy” in newborns.1 Baran and colleagues further defined it as “congenital malalignment of the big toenail” a year later.2 Few case studies exist so determining the frequency of the condition is difficult. Judging from the literature that reports patient characteristics, it appears females are more affected than males. A genetic component has been hypothesized but Baran and coworkers felt that an abnormal pull of the extensor hallucis tendon causes the lateral portion of the nail matrix to be displaced proximally.2 This has the validation of magnetic resonance imaging (MRI) studies, which showed a hypertrophy of the dorsolateral aspect of the extensor tendon.3,4
The hallmark of this nail condition is a lateral deviation of the nail plate with respect to the distal phalanx’s longitudinal axis that is present at birth.5 The nail loses its natural color and presents as yellow, green, gray, black or brown. If green discoloration is present, there may be Pseudomonas colonization. If brown or black discoloration is present, there may be a subungual hemorrhage or fungal infection. Wave-like transverse ridging across the nail plate gives the nail an oyster shell-like appearance. The free end of the nail may appear pointed or triangular. The condition mostly occurs bilaterally with only hallux involvement and may overlap with hallux valgus.
As the nail progresses towards the distal tip, it becomes onycholytic and thickened. As the nail loses contact with the nail bed, a distal wall of skin may build up, which further prevents the nail from growing forward longitudinally. Onychocryptosis and possible paronychia may develop as the nail continues to take its curvilinear path toward the second digit.
A Guide To The Differential Diagnosis
Onychomycosis. Onychomycosis or tinea unguium is caused by invasion of the nail unit by dermatophytes, non-dermatophyte molds, and/or Candida albicans. Clinicians may see concomitant tinea pedis or tinea cruris in patients with onychomycosis.