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What is an ingrown toenail? - The diagnosis


The ingrown toenail, in medical jargon also Unguis incarnatus (International classification of the disease ICD 10: L60.0), or onychocryptosis, is diagnosed when the nail does not grow in the intended path, but grows into the adjacent skin from the side. An ingrown toenail can cause recurring symptoms in the form of pain at the edge of the nail, inflammation with suppuration, redness and swelling in the soft tissues. In the advanced stage, granulation tissue forms, so-called Caro luxurians. Any pressure on the irritated nail edge is experienced as extremely painful by those affected. In the worst case, the inflammation can also spread to the bone.

Eingewachsener Zehennagel wächst durch die Kuppe vor Laserbehandlung
Rollnagel vor Laser Behandlung

Examples of Ingrown Toenail Shapes:

Severely ingrown nail, that grows through the tip of the toe in front

Classic roll nail(genetically conditioned)

Chronische Entzündung wildes Fleisch Zehennagel

Ingrown toenail with Caro luxurians, granulation tissue

Rollnagel wächst in die Haut seitlich

Severely ingrown nail on one side 

How do you get an ingrown toenail? - The reasons

The causes for the ingrowth of the nail and subsequent inflammation can be varied:

  1. Genetics:
    In some people, the root of the nail is genetically too wide, so that the side edges of the nail can cut into the skin with age. Often the parents or grandparents have already had similar problems.


  2. Wrong cutting:
    Another cause of nail ingrowth is when the nail is trimmed too round and trimmed too low on the lateral edges. This forms a deep nail tip that grows into the tip of the toe.


  3. Foot deformity when walking:
    Rolling over the toes (“walking on tiptoe”, high heels) and the associated increased pressure puts more strain on the nail edges.


  4. Shoes that are too tight:
    With narrow or pointed shoes, the nail is pressed more strongly into the soft tissue (skin) due to the permanent pressure and can cut more easily.


  5. Foot or Toe Deformation:
    In the case of existing pre-existing conditions, eg hallux valgus (axial deviation of the big toe), fallen arches, flat feet, the anatomy of the toe changes. The neighboring toes constantly press on the nail edge of the big toe.


  6. Nail trauma:
    Nail trauma from impacts or injuries can lead to structural changes in the nail with ingrowth of the edge as a result of permanent changes in the shape of the nail bed or the nail root. 


  7. Nail diseases:
    In the case of fungal infestation, the nail can also develop changes in shape that promote ingrowth.


  8. Overweight:
    High body weight (obesity) increases the edge pressure of the nail, causing it to cut more into the skin.

  9. Pregnancy:
    If you are pregnant, the water retention causes tissue swelling. This can put pressure on the edge of the nail, which can lead to inflammation.

  10. Medicines:
    Taking cancer medications or other medications that lower the immune system. (E.g. in rheumatism).

  11. Existing diseases:
    Various diseases such as diabetes mellitus or venous insufficiency or special nail diseases (roll nail) promote the ingrowth of the toenails.

Eingewachsener Nagel Vorbereitung vor Laserbehandlung

Preparation for a laser treatment

Eingewachsener Zehennagel Ursache

Ingrown toenail with inflammatory response

Eingewachsener Zehennagel Aussehen

Nail shape changes that a can cause the nail edge to grow into the skin

Formen von Rollnägel eingewachsen

Rolled nails that cut into the skin


How common is an ingrown toenail? - The frequency

Ingrown toenail is common. It occurs in about 20 out of 100 patients with foot problems. The ingrown nail can occur on the fingernails as well as toenails, although it is more common on the toes.

eingewachsener Fingernagel

Ingrown Fingernail 

Do I have an ingrown toenail? - The symptoms


The following symptoms indicate an ingrown toenail:


  • pain to touch (“sheets already hurt”)

  • redness 

  • swelling

  • throbbing on the lateral edge of the nail

  • hot sensation at the edge of the nail

  • leakage of wound fluid

  • inflammation with pus

  • recurring pain


Avoidance strategies: 


  • change in gait to shift the load pressure of the shoes

  • buy footwear one size larger

  • refraining from sporting activities and heavy strain on the toes = restriction in everyday life

  • dangling your foot out of bed (avoiding the pressure of the duvet)

Symptome eingewachsener Zehennagel

Ingrown toenail with swelling

When to see a doctor for an ingrown toenail? - The stadiums


A distinction is made between acute forms and chronic forms of ingrown toenails.

In the acute forms, painful swelling, redness and weeping inflammation can occur in a short time. 


One speaks of a chronic form when there is an unchanged inflammatory process lasting several weeks, up to and including suppuration. It is the weakened acute form over a long period of time. The risk of developing inflammatory bone involvement is particularly high here.


The ingrown toenail develops in 4 stages:


Stage 1:

ingrown toenail without permanent discomfort 

Stage 2:

part of the nail pricks deep into the soft tissue, pain occurs at the edge of the nail, and tissue irritation begins

Stage 3:

there is tissue swelling with pressure pain, the reddening is an indication of bacterial colonization of the deep wound, oozing of the wound, a doctor should be consulted at this stage at the latest

Stage 4:

Infection, suppuration, increase in swelling, appearance of wild flesh (granulation tissue), bleeding, migrating inflammation in the direction of the body, suppuration can spread to the bones, a doctors visit is unavoidable

Stadien des eingewachsenen Zehennagels

stage 1

stage 2

stage 3

stage 4

How to treat an ingrown toenail at home? 

In the first two stages  there are alternative treatment options:

  1. Removal of the nail edge by the podiatrist, the nail does not have to be completely removed

  2. Anti-inflammatory antibiotic ointments

  3. Nail-brace treatment

  4. Foot baths, also with curd soap additive 

If the inflammation of the wound decreases again and the nail spike could be removed, conservative treatment may have been sufficient. In stage 3 at the latest, surgery must be carried out because the treatment is only successful if the cause of the disease is eliminated. Persistent and recurrent stage 2 symptoms also lead to surgical treatment. The aim of the treatments is to remove the nail parts from the wound and to narrow the nail root to prevent new edging.

Nagelspange beim eingewachsenen Zehennagel, konservative Behandlungsmaßnahme

Nail brace treatment ingrown toenail

konservative behandlung

What surgical procedures are there for ingrown toenails?

operative behandlung

1. Our laser treatment 

After the part of the nail has been removed from the side, the outer part of the nail root is removed with laser pulses of approx. 0.1 mm in milliseconds using a pulsed Co2 laser under local anesthesia. The precise, pinpoint removal of the nail root takes place under the skin without the use of a scalpel and does not require any major tissue removal as is the case with Emmert incision operation. The healing process can be significantly shortened by the freedom from incisions. Patients can walk normally immediately after treatment and report little  postoperative pain, no painkillers are required.Compared to other treatment strategies, we see laser treatment as a modern, precise and gentle method for treating ingrown toenails. To date, we have carried out over 13,000 patient treatments nationwide. Looking back on our 23 years of application experience, the very high sustainability of the procedure and the positive patient experiences are particularly interesting. 

2. Phenolization (burning) of the lateral nail root

The procedure involves a so-called phenol matrix ablation. When a strip of nails has been removed, a rod soaked in phenol is rotated 3 x 1 min in the area of the nail root. This is intended to chemically destroy the lateral root. The phenol works wherever it hits. It can also attack and destroy cells in healthy tissue, which can lead to local damage (ulcerations) with subsequent scarring. The phenol is also not harmless for the user and is only approved for the treatment of ingrown nails. The DFG (German Research Association) has classified phenol as a critical substance in terms of toxicity. Phenol is considered carcinogenic.


3. Electrocautery (electric sclerotherapy)

Instead of phenolization, the nail root is sclerosed by applying electricity. So-called electrocoagulation is firmly established in surgical medicine. In very small areas (nail root), the difficulty lies in dosing the planar heat impulse and limiting its depth expansion. The heat input locally is large. This method is used less often.


4. Emmert plastic / nail root removal (cutting operation)

The incision operation according to Emmert, also called nail wedge excision, was first mentioned around 1850 and has been used ever since. During the operation, the skin is cut parallel to the long side of the nail with a scalpel in the shape of a wedge, a lateral wedge of tissue including the nail portion and the too wide nail root is removed down to the bone. The tissue defect is then closed with sutures. The operation is performed under local anesthesia. The wound healing can take up to 4 weeks, the foot must be elevated and rested. The sutures are removed after 14 days. An elongated scar often remains visible. After the Emmert plastic surgery, approx. 20 - 30% have recurrences, i.e. nails that grow back in, even after several surgical interventions. Many patients report a long healing process and a longer inability to work or exercise. Postoperatively, a tissue scar remains on the toe due to the cut, the nail is visibly narrowed on one side. Emmert plastic is the most common surgical method for ingrown toenails in Germany.A variant of the Emmert operation is the selective removal of the nail root without removing the lateral soft tissue. This method also requires an incision in the toe, since the root cannot be reached in any other way. 


Tada H et al (2004) Clinical comparison of the scanning CO2 laser and conventional surgery in the treatment of ingrown nail deformities. J Dermatologist Treat 15:387-390

Heidelbaugh JJ, Lee H (2009) Management of the ingrown toenail. Am Fam Physician 79:303-308

Eekhof JA, Van Wijk B, Knuistingh Neven A, van der Wouden JC. Interventions for growing toenails. Cochrane Database System Rev 2012; (4): CD001541.

Yang KC, Li YT (2002) Treatment of recurrent ingrown great toenail associated with granulation tissue by partial nail avulsion followed by matricectomy with sharpulse carbon dioxide laser. Dermatol Surg 28:419-421

N Moellhoff, H Polzer, SF Baumbach, KG Kanz, W Böcker & V Bogner-Flatz, Der Unfallchirurg volume 124, pages 311-318 (2021 Unguis incarnatus—conservative or operative treatment? A practical treatment algorithm

Wollina U, Nenoff P, Haroske G, Haenssle HA (2016) The diagnosis and treatment of nail disorders. Dtsch Arztebl Int 113:509-518

Strube H‑D, Wasserscheid B (1990) Emmert plasty in Unguis incarnatus. Operat Orthop Traumatol 2:39-45

Mainusch OM, Loser CR (2018) Ingrown toenails-options for daily practice. Dermatologist 69:726-730

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