Ingrown Toenail (Onychocryptosis)

 

Introduction

An "ingrown toenail” is a common condition that occurs when the toenail plate grows into the periungual skin resulting in pain, inflammation and sometimes infection.  It most commonly affects the big toe.

 

Risk Factors

  • Improper nail trimming: too short and contoured with the toe rather than square
  • Tight footwear
  • Poor foot hygiene or hyperhidrosis
    • sweat softens the skin around the nail making it easier for the nail to embed itself
    • sweating predisposes to infection
  • Fungal infection (can cause nail to thicken or widen)
  • Congenital (pincer-nail deformity, wide nail plate, malalignment of the toenails)
  • Trauma
  • Use of epidermal growth factor receptor inhibitors (cetuximab)

 

Anatomy of a Toenail

 

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Clinical Features

  • Can affect one or both nail edges (lateral more common than medial) or, rarely, the end of nail can grow into the skin
  • Most commonly affects the hallux
  • Most common in teenagers

Early symptoms: hard, swollen and tender nail edge

Later symptoms: erythema, inflammation and pain

Chronic symptoms: hypertrophic granulation of skin around toe

Infection features: worsening inflammation, pain and discharge (blood or pus), systemically unwell

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Ingrown toenail

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Infected ingrown toenail

Reference:  https://www.nhs.uk/conditions/ingrown-toenail/

 

Differential Diagnosis

  • Subungual exostosis
  • Tumours of nail bed - benign/malignant (e.g. melanoma or subungual SCC)

 

Treatment

Prevention

  • Cut toenails straight across and no shorter than the edge of the toe
  • Feet hygiene 
  • Properly-fitting footwear

Non-surgical treatment

Indication: mild to moderate lesions

Early treatment helps to prevent infection

  • Soak the foot in warm, salty water 3 times per day (to soften the skin around the toe and reduce risk of infection)
  • Keep the foot dry for the rest of the day.
  • Wear comfortable, spacious shoes or sandals until symptoms improve
  • Simple analgesia for pain: ibuprofen or paracetamol
  • Using a cotton-bud to push the skin away from the nail 
  • Use of dental floss to lift the edge of the embedded ingrown toenail 
  • An infected toe requires medical assessment with oral antibiotics
  • Do not cut nail short

Surgical Treatment

Indication: persistent inflammation and recurrent infection 

  • Wedge resection of toenail and nail fold (excision of the affected portion of nail plate, partial matricectomy, wedge dissection of the nail bed and hypertrophic nail fold) 
  • Excision of affected nail
  • Chemical matricectomy (ablation of matrix) using phenol
  • Under local anaesthetic ring block
  • Revision surgery requires a more aggressive approach

*Simple nail avulsion alone has up to 70% recurrence rate

 

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Reference:  https://orthoinfo.aaos.org/en/diseases--conditions/ingrown-toenail

 

 

References

  • Park DH, Singh D. The management of ingrowing toenails. BMJ. 2012 Apr 3;344:e2089. doi: 10.1136/bmj.e2089. PMID: 22491483
  • Cho SY, Kim YC, Choi JW. Epidemiology and bone-related comorbidities of ingrown nail: A nationwide population-based study. J Dermatol. 2018 Dec;45(12):1418-1424. doi: 10.1111/1346-8138.14659. Epub 2018 Sep 28. PMID: 30264897
  • Romero-Pérez D, Betlloch-Mas I, Encabo-Durán B. Onychocryptosis: a long-term retrospective and comparative follow-up study of surgical and phenol chemical matricectomy in 520 procedures. Int J Dermatol. 2017 Feb;56(2):221-224. doi: 10.1111/ijd.13406. Epub 2016 Oct 12. PMID: 27734499