Last reviewed: 10 Apr 2021
Last updated: 24 Mar 2020



History and exam

Key diagnostic factors

  • presence of risk factors
  • pain, swelling, drainage (acute)
  • swollen, purulent nail fold (acute)
  • nail plate irregularities (chronic)
  • swelling/redness of nail folds (chronic)
  • pink, swollen nail folds (chronic)
  • missing cuticle (chronic)
  • underlying nail plate abnormalities (chronic)

Risk factors

  • microscopic or macroscopic injury to the nail folds (acute)
  • occupational risks (acute and chronic)
  • barrier damage to the nail folds, cuticle (chronic)
  • ingrown nail
  • chemotherapeutic agents
  • toddler and adult
  • female

Diagnostic investigations

1st investigations to order

  • swab for Gram stain, culture, and sensitivity (acute or acute-on-chronic)
  • swab for Tzanck smear (acute, herpetic)

Investigations to consider

  • potassium hydroxide or fungal culture (chronic)
  • x-ray
  • MRI
  • biopsy of skin/bone

Treatment algorithm


Dermatology Consultant

Charing Cross Hospital

Imperial College NHS Trust




SZ declares that she has no competing interests.

Specialty Registrar in Dermatology

Charing Cross Hospital

Imperial College NHS Trust




KH declares that he has no competing interests.

Dr Shirin Zaheri and Dr Khawar Hussain would like to gratefully acknowledge Dr Catherine Hardman, Dr Nathaniel J. Jellinek, Professor C. Ralph Daniel III, and Dr Shaimaa Nassar, previous contributors to this topic. 


NJJ, CH, and SN declare that they have no competing interests. CRD is an author of a number of references cited in this topic.

Peer reviewersVIEW ALL

Assistant Professor of Clinical Dermatology

Columbia University

New York



RU declares that he has no competing interests.

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