Ingrown toenail

Meet the patient

A 19-year-old runner limps in after a week of cutting the corner of his great toenail "to relieve the pressure". The lateral fold is red, weeping, exquisitely tender, with a beefy nub of granulation tissue overhanging the nail edge. He wants antibiotics. The spicule he left behind is the actual disease.[1]

Hold two questions for the whole topic: is the nail edge still piercing the fold? and whose toe is this — a healthy adolescent, or a diabetic foot where a clinic procedure becomes a limb threat? Everything below hangs off those two.[1]

One spicule, three stages — the Heifetz ladder

The nail is a foreign body, and the fold reacts in a predictable sequence. The practical three-stage ladder (Heifetz-style, and the one examiners reward) maps directly onto treatment:[1]

1. Stage 1 — inflammation. Erythema, oedema, pain on pressure; skin still intact. The fold is angry but not yet breached.
2. Stage 2 — infection. Seropurulent discharge and worsening pain; the spicule has broken the skin and the flora have walked in.
3. Stage 3 — chronic hypertrophy. Proud, fleshy granulation tissue — often mistaken for a pyogenic granuloma — overgrows the nail edge and traps it deeper.[1][2][3]

The stages are not just descriptive: each one names the treatment. Stage 1 is conservative, stage 2 needs the spicule out, stage 3 needs the matrix.[1]

The spicule is the disease — microbes are the passenger

A nail edge — usually a sharp spicule from rounding the corner or cutting too short — pierces the lateral fold and behaves as a foreign body. Local inflammation swells the fold, the skin breaks down, skin flora (staphylococci leading) colonise the wound, and chronicity grows granulation tissue that buries the nail deeper still. It is a self-perpetuating cycle, and breaking it means removing the spicule — not just sterilising the skin.[1][3]

The classic trap: everyone reaches for antibiotics first. Antibiotics calm the cellulitis but cannot dislodge a nail spicule embedded in flesh, so the infection recurs the moment the course ends. Mechanical relief comes first, always.[1]

A consultant confession: the commonest reason a patient comes back is that someone pulled the nail out without touching the matrix. The lateral matrix simply regrew the same pathological edge. Avulsion treats today; matrixectomy treats tomorrow.[4][5]

Who gets it — and why

It peaks twice: in adolescents and young adults (tight shoes, sport, sweaty feet, amateur nail surgery), and again in older people with dystrophic, thickened nails. The reproducible risk factors are tight or pointed footwear, improper cutting (rounding the corners or trimming too short and leaving a spicule), hyperhidrosis, trauma, a genetically wide or pincer nail plate, obesity, and repetitive athletic stress.[1][3]

Diabetes and peripheral arterial disease do not cause the spicule — but they transform a trivial portal of entry into a limb-threatening one, which is why you check the pulses and the glucose before ever reaching for the phenol.[1]

The differential — name the mimic, name the discriminator

Most ingrown nails announce themselves; the traps are the look-alikes:[6]

• Acute paronychia — fold infection without true nail embedding; the edge is not piercing the skin.
• Toe cellulitis or web-space infection — spreading, warm, systemic; the nail itself is innocent.
• Onychomycosis with dystrophy — distorting the nail and coexisting with the embedding rather than causing it.
• Subungual exostosis — a bony spur lifting the nail; X-ray the atypical case.
• Retronychia or pincer nail — proximal embedding or transverse over-curvature; different anatomy, different fix.
• Malignancy (SCC, melanoma) masquerading as a single, chronic, non-healing granulating lesion — biopsy the odd one.[6]

Everyone forgets: a "stubborn ingrown toenail" on one digit that will not heal is subungual squamous cell carcinoma until a biopsy says otherwise. Photograph or biopsy anything that does not fit the mechanical story.[6]

At the bedside — before you touch the nail

Inspect the footwear, the gait, and the nail-cutting habit — the history often hands you the cause. Stage the inflammation, look for the spicule, gently separate the fold to find any abscess, and note the granulation tissue. Then do the safety checks the junior forgets: palpate both pedal pulses, check capillary refill, screen sensation, and document diabetes status. Reserve imaging for suspected osteomyelitis or bony exostosis, a swab for organism-guided therapy in significant infection, and an HbA1c for recurrent or severe disease.[1][2]

Management — match the stage, not the habit

The ladder is stage-driven, and the cardinal rule is that antibiotics never substitute for mechanical relief.[1]

[1]

Antibiotics — when they actually help. Reserve them for spreading cellulitis, lymphangitis, or systemic features: rest, elevation, and an oral anti-staphylococcal agent covering skin pathogens per local formulary (for example flucloxacillin 500 mg four times daily orally for uncomplicated cellulitis where MSSA is likely and there is no allergy).[1]

Stage 1 in practice is warm soaks, elevation, wide shoes, straight-across cutting, and a cotton-wick or gutter-splint pack beneath the offending edge to guide the nail out over the fold — plus a firm instruction to stop digging at the corners, because most recurrences are self-inflicted.[1][2]

Stage 2 in practice is draining any pus, performing a digital block and partial avulsion of the offending lateral strip to remove the foreign body at once, and adding antibiotics only for true spreading cellulitis, not for discharge alone.[1][3]

Stage 3 or recurrent in practice is the definitive step: partial matrixectomy of the lateral horn to cut recurrence, with chemical ablation by phenol applied carefully to the lateral matrix after avulsion. Protect the surrounding skin, irrigate per protocol, and warn that oozing and delayed healing over a few weeks are expected. Surgical matrix excision and alternative caustics (sodium hydroxide) are used in some services.[1][4][5]

Why avulsion alone fails — the matrix always wins

This is the single most examinable idea in the topic, and the one juniors get wrong. Pulling the whole nail out relieves today's spicule, but the lateral matrix is left intact and regrows the same pathological edge — so recurrence after plain avulsion is high. Phenol matrixectomy destroys the corner of matrix that produces the offending edge, which is why it is the definitive answer for recurrent and stage-3 disease. Combination surgical-plus-phenol approaches are widely studied precisely because they cut recurrence to a fraction of avulsion alone.[4][5]

When the toe is not just a toe — the red flags

[1]

The other red flags are the spreading infections — cellulitis, lymphangitis, fever, suspected osteomyelitis — needing systemic antibiotics and imaging, and the single chronic non-healing nail-unit lesion without a mechanical story, which is biopsy territory to exclude squamous cell carcinoma or melanoma.[1][6]

Special populations — tailor the aggression

Children lean towards maximal conservative care; reserve procedures for recurrent or severe disease. Athletes need footwear modification — it is half the cure. Diabetic and vasculopathic patients carry a lower infection threshold and need offloading and vascular assessment before any procedure. Anticoagulated patients need a coordinated peri-procedure plan. In pregnancy, prefer conservative measures and discuss chemical matrixectomy only if the benefits clearly outweigh the theoretical risks and local policy permits.[1]

Prognosis and where to refer

Mild disease often settles with education and packing alone. Recurrence after definitive lateral matrixectomy is substantially lower than after temporary avulsion, which is why the matrix — not the nail — is the target in recurrent disease.[5] Refer to podiatry, dermatologic surgery, or orthopaedics for recurrent stage-3 disease, diagnostic doubt, or the high-risk foot.[1]

The evidence, and where practice varies

American Family Physician reviews give the practical primary-care algorithm for staging and procedures.[1][2] Indian and international dermatology reviews emphasise the matrixectomy options and acknowledge local resource variation.[3] Phenol-application technique papers and comparative matrixectomy trials underpin chemical ablation as a core skill.[4][5] Where practice varies, it is in agent choice — phenol versus sodium hydroxide versus surgical excision — and in who delivers the procedure: podiatry, dermatology, or primary care.[6]

The mnemonic, and the mantra

[1]

Etymology for viva gold: onychocryptosis is Greek — onyx, nail, plus kryptos, hidden — the nail edge hidden in the flesh. Matrixectomy is exactly what it says: excision (or chemical destruction) of the matrix that grows the nail.[1]

The mantra: mechanical disease first, microbes second — cut straight, avulse the spicule, ablate the matrix for recurrence, and never phenol a cold toe.[1]

Ward-round test — three stems, thirty seconds each

Stem 1 — the runner who cut the corner (answer)

A 19-year-old runner has a stage-2 ingrown great toenail with seropurulent discharge but no spreading cellulitis. He asks for "a course of antibiotics and to be left alone". What do you actually do? Model: Antibiotics alone will fail — the retained spicule is the disease. Drain any pus, perform a digital block and partial avulsion of the offending lateral nail strip, then pack and dress. Add an oral anti-staphylococcal antibiotic only if there is true spreading cellulitis or systemic features. Counsel straight-across cutting and wide shoes, and book phenol matrixectomy if it recurs.[1]

Stem 2 — the third visit for the same toe (answer)

A patient is back for the third time after repeated plain nail avulsions; each time the edge regrows and embeds. What is the definitive step, and why does plain avulsion keep failing? Model: Plain avulsion removes today's spicule but leaves the lateral matrix intact, which regrows the same pathological edge — hence the recurrence. The definitive step is partial matrixectomy with phenol chemical ablation of the lateral matrix, which destroys the cells producing the offending edge and cuts recurrence dramatically versus avulsion alone.[4][5]

Stem 3 — the diabetic with a weeping toe (answer)

A 62-year-old with diabetes and neuropathy has an ingrown toenail with surrounding erythema extending onto the dorsum of the foot. Pulses are diminished. The registrar offers to phenolise it in clinic today. What is the right call? Model: Stop. This is not a routine clinic phenol — diminished pulses, neuropathy, and spreading cellulitis on a diabetic foot put it on the multidisciplinary diabetic-foot pathway: assess tissue perfusion and viability, give systemic antibiotics for the cellulitis, image if osteomyelitis is suspected, and defer elective matrixectomy until the foot is safe. An elective procedure on a poorly perfused toe can cost the limb.[1]

References

1. [1]Mayeaux EJ Jr, Carter C, Murphy TE. Ingrown Toenail Management Am Fam Physician, 2019.PMID 31361106
2. [2]Heidelbaugh JJ, Lee H. Management of the ingrown toenail Am Fam Physician, 2009.PMID 19235497
3. [3]Khunger N, Kandhari R. Ingrown toenails Indian J Dermatol Venereol Leprol, 2012.PMID 22565427
4. [4]Becerro de Bengoa Vallejo R, Losa Iglesias ME, Sanchez Gomez R, Jules KT. Gauze application of phenol for matrixectomy J Am Podiatr Med Assoc, 2008.PMID 18820047
5. [5]Isik C, Cakici H, Cagri Kose K, et al. Comparison of partial matrixectomy and combination treatment (partial matrixectomy + phenol) in ingrown toenail Med Glas (Zenica), 2013.PMID 23348167
6. [6]Lee DK, Lipner SR. Optimal diagnosis and management of common nail disorders Ann Med, 2022.PMID 35238267