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Ingrown Toenail

Ingrown Toenail is a topic covered in the 5-Minute Clinical Consult.

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  • In an ingrown toenail, the distal margin of the nail plate grows into the lateral nail fold, causing irritation, inflammation, and sometimes bacterial or fungal infection:
    • Stage 1 (inflammation): erythema, edema, tenderness to palpation of lateral nail fold
    • Stage 2 (abscess): increased pain, erythema, and edema as well as drainage (purulent or serous)
    • Stage 3 (granulation): Chronic inflammation leads to further erythema, edema, and pain, often with granulation tissue growing over the nail plate and significant nail fold hypertrophy.
  • Can reoccur
  • Synonym(s): onychocryptosis, unguis incarnatus


  • Great toenail is most often affected.
  • Lateral edge of nail is more commonly affected than the medial edge.
  • Most common in males aged 14 to 25 years
  • Infrequent, but more often in elderly females than in elderly males
  • More common in those with lower incomes

  • 24.5/1,000 overall
  • 50/1,000 ≥65 years

Etiology and Pathophysiology

  • Nail plate penetrates the nail fold causing a foreign body reaction (inflammation).
  • Bacteria or fungi may enter through the opening in the nail fold, causing infection and abscess formation.
  • The inflamed and infected area leads to granulation tissue and hypertrophy of the nail fold.

Risk Factors

  • Genetic factors
    • Increased nail fold width
    • Decreased nail thickness
    • Medial rotation of the toe
  • Many others proposed; none proven, including the following:
    • Distorted, thickened nail (onychogryphosis)
    • Fungal infection (onychomycosis)
    • Hyperhidrosis
    • Improper trimming of the lateral nail plate
    • Poorly fitting shoes
    • Trauma to nail or nail fold
    • Conditions that predispose to pedal edema (i.e., thyroid dysfunction, diabetes, obesity, heart failure, renal disease)

General Prevention

  • Properly fitting shoes
  • Proper nail trimming (see “Patient Education”)

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Stephens, Mark B., et al., editors. "Ingrown Toenail." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2019. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116870/all/Ingrown_Toenail.
Ingrown Toenail. In: Stephens MB, Golding J, Baldor RA, et al, eds. 5-Minute Clinical Consult. 27th ed. Wolters Kluwer; 2019. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116870/all/Ingrown_Toenail. Accessed March 22, 2019.
Ingrown Toenail. (2019). In Stephens, M. B., Golding, J., Baldor, R. A., & Domino, F. J. (Eds.), 5-Minute Clinical Consult. Available from https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116870/all/Ingrown_Toenail
Ingrown Toenail [Internet]. In: Stephens MB, Golding J, Baldor RA, Domino FJ, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2019. [cited 2019 March 22]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116870/all/Ingrown_Toenail.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Ingrown Toenail ID - 116870 ED - Stephens,Mark B, ED - Golding,Jeremy, ED - Baldor,Robert A, ED - Domino,Frank J, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116870/all/Ingrown_Toenail PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -