BASICS
DESCRIPTION
- Onychogryphosis describes claw-like hypertrophy and thickening of the entire nail plate, involving most commonly the great toe, leading to severely distorted, brownish, spiraled nails detached from the nail bed.
- The exaggerated growth of the nail is usually upward/lateral, with superficial transverse striations, and pain can be elicited with applied pressure.
EPIDEMIOLOGY
Prevalence
Onychogryphosis occurs in 5% of the world population.
ETIOLOGY AND PATHOPHYSIOLOGY
- The nail bed matrix produces the nail plate at uneven rates.
- It is thought the faster growing side of uneven keratin production at the nail bed determines the direction of the nail deformity (1).
- Several proposed theories for the cause of onychogryphosis:
- Pressure or friction from footwear
- Decreased perfusion secondary to peripheral vascular disorders
- Onychomycosis
- Self-neglect
- Hallux valgus
- Systemic diseases such as:
- Ichthyosis
- Psoriasis
- Hyperuricemia
- CNS diseases
- Syphilis, pemphigus, and variola
- Leishmaniasis
- Hansen disease
- Autosomal dominant condition, where the nails of the hands and the feet are involved, most notably in the 1st year of life.
Genetics
Autosomal dominant in some cases
RISK FACTORS
- Playing high-friction sports, such as football
- Older individuals
- Subungual epidermophytosis
- Hyperuricemia
- Diabetes mellitus
GENERAL PREVENTION
- Avoid injuries to the fingers and toes.
- Avoid compact footwear.
- Avoid nail polish, as this causes trapping of moisture under the nail.
COMMONLY ASSOCIATED CONDITIONS
- Psoriasis
- Ichthyosis
- Tinea unguium
DIAGNOSIS
HISTORY
- Onychogryphosis is easily detected in the later stages when the changes are severe; however, in the early stages of mild hypertrophy, the diagnosis may be difficult to determine.
- Often found in individuals who are homeless, institutionalized, or have poor hygiene
- Most commonly affects the hallux and presents as a thickened, brown nail plate on a hyperplastic nail bed
- Onychogryphosis develops chronically and lasts months to years.
PHYSICAL EXAM
- Nail plate thickening with gross hyperkeratosis and increased curvature of the nail plate, either downward (called oyster-like onychogryphosis) or upward (also known as ram 's horn dystrophy) (2)
- Thickened (onychauxis), opaque, brownish nails, either laterally or upwardly displaced on the toe and/or finger
- Leukonychia (white nails) is often seen.
- The bend of the nail is accentuated by other foot anomalies such as hallux valgus.
DIFFERENTIAL DIAGNOSIS
- Onychomycosis
- Psoriasis
- Pachyonychia congenital
- Congenital onychodystrophy of the index fingers (COIF, Iso-Kikuchi syndrome)
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (labs, imaging)
- Potassium hydroxide (KOH) microscopy, fungal culture, and/or histopathologic examination with periodic acid-Schiff (PAS) stain of the nail clippings should be performed to rule out fungal infection.
- Nail biopsy may be necessary to distinguish from tinea unguium that coexists with onychogryphosis (3)[B].
Test Interpretation
Hyperkeratotic nail bed (3)
TREATMENT
MEDICATION
First Line
- Periodic clipping with 40% urea (3)[A]
- Trimming by a podiatrist (3)[B]
- Avulsion of the nail plate with surgical destruction of the matrix with phenol or the CO2 laser
- Antifungal medication if concurrent fungal infection detected
Second Line
Reducing the hyperkeratotic nails with nail drills and burs is effective. However, it was noted that particles 0.5 to 5 ¼m were released from the reduction and, if repeatedly inhaled into the respiratory tract, can lead to conjunctivitis, rhinitis, asthma, cough, and hypersensitivity (3). Nail reduction with these methods should therefore be done with caution.
SURGERY/OTHER PROCEDURES
- Vascular impairment can often occur in conjunction with onychogryphosis; a vascular assessment is warranted and bypass surgery may be indicated.
- Saturated solution of phenol should be applied after the nail has been removed to reach all parts of the germinal matrix (3)[C].
- In low-risk patients (those without diabetes, peripheral vascular disease, etc.), the following procedures should be performed (4)[C]:
- Surgical resection
- CO2 surgical laser
- Phenolization
ONGOING CARE
PATIENT EDUCATION
- Educate the patient to avoid:
- Tight-fitting footwear
- Nail polish
- Nails should be kept trimmed.
PROGNOSIS
- Onychogryphosis has an excellent prognosis; however, treatment must be continued for 3 months and, in some cases, up to 1.5 years (5).
- Prolonged treatment is needed while new nail replaces the distorted nail.
- The goal is to control symptoms by keeping the nail short. Cure is not often necessary or achievable.
COMPLICATIONS
- The danger of the excessive pressure from the nail keratin distally bending and turning under the nail is subungual hemorrhage and gangrene, especially in the presence of diabetes or peripheral vascular disease (4).
- Fungal infection of the affected nail(s)
REFERENCES
11 Betti S, Bassi A, Prignano F, et al. A lifelong onychogryphosis. G Ital Dermatol Venereol. 2009;144(4):502 " 503.22 Nath AK, Udayashankar C. Congenital onychogryphosis: leaning tower nail. Dermatol Online J. 2011;17(11):9.33 Alavi A, Woo K, Sibbald RG. Common nail disorders and fungal infections. Adv Skin Wound Care. 2007;20(6):346 " 357.44 Bernard O. Onychogryphosis and the involuted nail in diabetes mellitus. West Indian Med J. 2011;50(Suppl 1):29 " 30.55 Singh G, Haneef NS, Uday A. Nail changes and disorders among the elderly. Indian J Dermatol Venereol Leprol. 2005;71(6):386 " 392.
CODES
ICD10
L60.2 Onychogryphosis
ICD9
703.8 Other specified diseases of nail
SNOMED
Onychogryposis
CLINICAL PEARLS
- A clinical diagnosis can be made by from the presentation of onychogryphosis: thickened, opaque, brown, laterally displaced nail.
- Continued podiatric care is essential to control this condition sufficiently.
- The physician must rule out onychomycosis with a KOH microscopy, PAS stain, or fungal culture.