USMLE Prep - Medical Reference Library

Nail Disorders — Onycholysis, Paronychia, and Psoriatic Nail

System: Dermatology • Reviewed: Aug 31, 2025 • Step 1Step 2Step 3

Synopsis:

Common nail disorders require etiology‑specific care: avoid moisture/trauma for paronychia; treat infections; manage psoriatic nail disease with topical/systemic therapy; correct underlying causes of onycholysis.

Key Points

  • Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
  • Use system-specific risk tools to guide testing and disposition.
  • Order high-yield tests first; escalate imaging when indicated.
  • Start evidence-based initial therapy and reassess frequently.

Algorithm

  1. Primary survey and vitals; IV access and monitors.
  2. Focused history/physical; identify red flags and likely etiologies.
  3. Order system-appropriate labs and imaging (see Investigations).
  4. Initiate guideline-based empiric therapy (see Pharmacology).
  5. Reassess response; arrange consultation and definitive management.

Clinical Synopsis & Reasoning

For Nail Disorders Onycholysis Paronychia And Psoriatic Nail, frame the differential by acuity and pathophysiology, then align diagnostics to the leading hypotheses. Prioritize stabilization while obtaining high‑yield studies such as CBC (Baseline hematology), BMP (Electrolytes/renal). Incorporate bedside imaging and targeted labs to define severity and identify complications; synthesize results with clinical trajectory to refine the working diagnosis and disposition needs.


Treatment Strategy & Disposition

Initiate disease‑directed therapy alongside supportive care, titrating to objective response. Pharmacologic options commonly include Analgesia/Antipyretics. Use validated frameworks (e.g., Therapeutic Pearls) to guide escalation and site of care. Address precipitating factors, de‑escalate empiric therapies with data, and arrange follow‑up for monitoring and risk‑factor modification; admit patients with instability, high risk of deterioration, or needs for close monitoring.


Management Notes

Avoid chronic moisture exposure; advise gloves for wet work. Trim detached nail to prevent further trauma.


Epidemiology / Risk Factors

  • Risk factors vary by condition and patient profile

Investigations

TestRole / RationaleTypical FindingsNotes
CBCBaseline hematologyAbnormal counts
BMPElectrolytes/renalDerangements

Therapeutic Pearls

ConditionFirst‑line
Acute paronychiaWarm soaks, I&D if abscess, antibiotics
Chronic paronychiaTopical steroids + antifungals; barrier protection
OnychomycosisOral terbinafine (labs for liver disease)
Nail psoriasisTopical/intralesional steroids; consider biologics
OnycholysisEliminate triggers; treat underlying conditions

Pharmacology

MedicationMechanismOnsetRole in TherapyLimitations
Warm soaks + topical mupirocinLocal care/antibacterialDaysMild acute paronychiaLocal irritation
Dicloxacillin/Cephalexin (PO)β-lactamDaysModerate infectionAllergy
TMP-SMX (MRSA risk)Folate antagonismDaysAlternativeHyperkalemia

Prognosis / Complications

  • Prognosis depends on severity, comorbidities, and timeliness of care

Patient Education / Counseling

  • Explain red flags and when to seek emergent care.
  • Reinforce medication adherence and follow-up plan.

References

  1. AAD Nail Disorders — Link