The Diagnosis and Treatment of Nail Disorders

Abstract

Background: Nail disorders can arise at any age. About half of all nail disorders are of infectious origin, 15% are due to inflammatory or metabolic conditions, and 5% are due to malignancies and pigment disturbances. The differential diagnosis of nail disorders is often an area of uncertainty.

Methods: This review is based on publications and guidelines retrieved by a selective search in PubMed, including Cochrane reviews, meta-analyses, and AWMF guidelines.

Results: Nail disorders are a common reason for derma - tologic consultation. They are assessed by clinical inspection, dermatoscopy, diagnostic imaging, microbiological (including mycological) testing, and histopathological examination. Some 10% of the overall population suffers from onychomycosis, with a point prevalence of around 15%. Bacterial infections of the nails are rarer than fungal colonization. High-risk groups for nail disorders include diabetics, dialysis patients, transplant recipients, and cancer patients. Malignant tumors of the nails are often not correctly diagnosed at first. For subungual melanoma, the mean time from the initial symptom to the correct diagnosis is approximately 2 years; this delay is partly responsible for the low 10-year survival rate of only 43%.

Conclusion: Evaluation of the nail organ is an important diagnostic instrument. Aside from onychomycosis, which is a common nail disorder, important differential diagnoses such as malignant diseases, drug side effects, and bacterial infections must be considered.

Figure 1:

anatomy of the nail organ (modified from Blausen.com staff. “Blausen gallery 2014”. Wikiversity Journal of Medicine. DOI:10.15347/wjm“2014.010. ISSN 20018762) Nail plate Cuticle Nail fold Nail matrix Nail bed

Figure 2:

the clinical and dermatoscopic features of common nail disorders a) and b): early subungual acrolentiginous melanoma. a) Clinical image of subungual blue discoloration in the area of the lunula. b) Dermatoscopy showing unstructured blueish-gray lunular pigmentation with incipient longitudinal pigment striae in the nail plate. c) and d): subungual invasive melanoma. c) Black pigmentation under the nail and also within the partially destroyed nail plate. Incipient Hutchinson phenomenon on the proximal nail fold and cuticle. d) Dermatoscopy showing longitudinal bands of varying widths and colors. e) and (f): Bowen’s disease of the nail bed. e) Clinical appearance resembling that of a chronic paronychia. f) Dermatoscopy showing partial destruction of the distal nail groove and hyponychium, together with the characteristic “dots along lines” pattern (red dots along dilated vessels)

Figure 3:

Onychomycoses a) Distal-lateral subungual onychomycosis due to T. rubrum in a 79-year-old man b) Onychomycosis of the big toenail in the same patient, with lateral white streaks. There is visible subungual hyperkeratosis of the markedly thickened nail plate, which is no longer transparent and manifests a yellowish-brown discoloration c) White superficial onychomycosis (leuconychia trichophytica) in a 41-year-old man d) Total dystrophic onychomycosis of the fingernails due to C. albicans and Aspergillus niger in an 88-year-old man