Board Review: Nail Disorders Differential Diagnosis

Overview / Definition Nail disorders encompass a wide range of conditions affecting the nails, which can arise from dermatological, systemic, or traumatic causes. Common nail disorders include onychomycosis, psoriasis, paronychia, and nail trauma, each presenting with unique clinical features and treatment considerations. Epidemiology Nail disorders are prevalent in both the general population and specific demographics. Key epidemiological insights include: Onychomycosis affects approximately 10% of the general population and up to 50% of adults over 60. Psoriasis affects around 2-3% of the population, with nail involvement seen in 50-80% of these patients. Paronychia is commonly seen in patients with occupational exposure to water or irritants. Pathophysiology / Mechanism The mechanisms underlying nail disorders can vary widely. For example: Onychomycosis: Fungal infections lead to keratin degradation. Psoriasis: Autoimmune dysregulation results in abnormal keratinocyte proliferation. Paronychia: Inflammation occurs due to infection or irritant exposure. Clinical Presentation Nail disorders can manifest in various ways, including: Onychomycosis: Thickened, discolored, and brittle nails. Psoriasis: Pitting, ridges, and nail separation. Paronychia: Red, swollen nail folds with possible pus formation. Diagnosis / Workup Diagnosis of nail disorders often involves: History taking: Assessing duration, symptoms, and potential exposures. Physical examination: Observing nail morphology and surrounding skin. Diagnostic tests: Nail clippings for fungal culture or histopathology as needed. Treatment / Management Management strategies vary depending on the specific nail disorder: Onychomycosis: Antifungal therapy (topical or systemic) such as terbinafine or itraconazole. Psoriasis: Topical corticosteroids, phototherapy, and systemic agents for severe cases. Paronychia: Warm soaks, topical antibiotics, and incision/drainage for abscess formation. Prognosis / Complications The pr