A 13-year-old boy presents with recurrent ingrown toenails. He presents to the clinic with another episode (Figure 162-1). He was treated with partial nail avulsion and a lateral matrixectomy was performed using topical phenol to ablate the matrix. This treatment produced long-term remission of his condition.

Onychocryptosis (ingrown toenails) is a common childhood and adult problem. Patients often seek treatment because of the significant levels of discomfort and disability associated with the condition.

Onychocryptosis, unguis incarnatus.

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  The prevalence of onychocryptosis is unknown as many patients do not seek medical care and it is not a reportable disease. The toenails, especially the great toenail, are most commonly affected. Ingrown toenails at birth and in early childhood do occur, but are very rare.

Onychocryptosis occurs when the lateral nail plate damages the lateral nail fold. The laterally edge of the nail plate penetrates and perforates the adjacent nail fold skin. Perforation of the lateral fold skin results in painful inflammation that manifests clinically as mild edema, erythema, and pain. In advanced stages, drainage, infection, and ulceration may be present. Hypertrophy of the lateral nail wall occurs, and granulation tissue forms over the nail plate and the nail fold during healing of the ulcerated skin.¹ It is a common affliction that can result from a variety of conditions that cause improper fit of the nail plate in the lateral nail grove (Figure 162-1).

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  Genetic predisposition.

  
  
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  Poor-fitting footwear.

  
  
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  Excessive trimming of the lateral nail plate.

  
  
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  Pincer nail deformity (Figure 162-2).

  
  
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  Trauma.

  
  
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  Sports in which kicking or running is important.

  
  
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  Hyperhidrosis.

  
  
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  Anatomic features such as nail fold width.

  
  
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  Congenital malalignment of the digit.

  
  
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  Overcurvature of the nail plate.

  
  
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  Onychomycosis and other diseases that result in abnormal changes in the nail plate.

  
  
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  Obesity causing deepening of the nail groove.

Clinical Features—History and Physical

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  The diagnosis is based upon clinical appearance and rarely is difficult. Characteristic signs and symptoms include pain, edema, exudate, and granulation tissue (Figure 162-1).

Typical Distribution

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  The great toe is most commonly affected; fingers are rarely involved except when nail biting is present.