ICD code S90.451S – Right great toe superficial foreign body, sequela

Key takeaways

S90.451S is a valid, billable ICD-10-CM code for a superficial foreign body of the right great toe at the sequela stage.

The seventh character S applies only after active healing has ended. Using A or D for a sequela visit is a leading denial trigger.

Sequela notes must link today’s condition to the original splinter, thorn, or fragment injury and code the residual condition first.

S90.451S is not an abrasion code. A healed right great toe abrasion is coded S90.411S instead.

ICD-10 Code S90.451S: Quick reference details

ICD-10 Code S90.451S is the billable code for a superficial foreign body of the right great toe at the sequela stage. It applies once the object is out, the skin has closed, and a residual effect brings the patient back.

The table below captures each field a coder or biller needs before submitting the claim.

What S90.451S means: Breaking down the code

S90.451S describes a superficial foreign body of the right great toe at the sequela stage of care. Each segment of the code narrows the meaning, read from left to right:

• S90: Superficial injury of ankle, foot and toes, the parent category within the S90-S99 ankle and foot block.
• S90.4: Other superficial injuries of toe, which narrows the site from the whole foot to the toes.
• S90.45: Superficial foreign body of toe, which sets the injury type.
• S90.451: Superficial foreign body of the right great toe, which adds the digit and the laterality. The great toe is also called the hallux.
• S: The seventh character for sequela, a residual condition left after the original injury has healed.

A superficial foreign body is an object such as a splinter, thorn, or glass sliver lodged in the outer skin layers. It is not an abrasion, which ICD-10-CM codes separately under S90.41-.

The S90-S99 block has Excludes2 notes for burns and corrosions (T20-T32) and fracture of ankle and malleolus (S82.-). It also excludes frostbite (T33-T34) and venomous insect bites or stings (T63.4). If the object passed below the skin surface, the puncture wound codes with foreign body (S91.14-) apply instead.

Clinical description: Superficial foreign body of the right great toe

A superficial foreign body injury of the great toe happens when an object embeds in the skin without reaching deeper structures. Barefoot steps onto splinters, glass, thorns, or metal slivers are the usual cause.

By the time S90.451S applies, the object has been removed and the skin has closed. The patient presents because the injury left a residual problem behind. Common sequelae after a right great toe foreign body include:

• Chronic localized pain at the entry site
• Scar tissue or a tender nodule where the object entered
• A foreign body granuloma from tissue reaction to the original material
• Altered sensation or reduced flexibility of the right great toe

Approximate synonyms for superficial foreign body, right great toe, sequela

• Sequela of foreign body in right great toe skin
• Late effect of splinter in right great toe
• Residual condition following superficial foreign body, right hallux

Understanding the seventh character ‘S’: Sequela defined

A sequela, as defined by the ICD-10-CM Official Guidelines (Section I.B.10), is a residual effect of an earlier illness or injury. It remains after the acute phase has ended. The seventh character S signals exactly that encounter type to payers and coding auditors.

Some coders take S to mean the patient is still recovering. Recovery belongs to the subsequent encounter, which uses seventh character D instead. The S character applies only when the original wound has closed and a residual effect remains.

For injury sequelae, Section I.C.19.a says the S goes on the injury code only. The code for the residual condition, such as a scar or a granuloma, is sequenced first, followed by S90.451S.

S90.451A vs S90.451D vs S90.451S: Choosing the right encounter type

The correct seventh character depends on where the patient is in their recovery, not on how many times they have been seen. The table below shows the clinical trigger for each variant.

Using S90.451A when the wound has already healed is a common denial trigger for this code family. The provider note must state that the active healing phase has ended before a sequela encounter is coded.

Clinically adjacent codes: What to use instead or alongside

Coders regularly meet laterality, site, and injury-type mismatches in this code family. The table below maps the closest adjacent codes and what separates each one from S90.451S.

Always specify laterality where documentation supports it. ICD-10-CM discourages unspecified codes when the medical record clearly identifies the affected side.

Three checks settle the code, in this order, and each one rules out a different neighbor before S90.451S is assigned.

Documentation requirements for sequela encounters

Four documentation elements should be in the medical record before S90.451S is assigned. A missing element gives a payer grounds to deny or downcode the claim. A medical billing compliance framework helps your team capture them at each encounter.

1. Link to the original injury. The note must reference the earlier right great toe foreign body, with its date and the object involved. The provider must also confirm that today’s problem stems from it.
2. Attestation that active healing has ended. The provider must state that the object was removed and the skin has fully healed. “Splinter removed in June, entry site now closed” is sufficient, while “patient returns for follow-up” is not.
3. Description of the current sequela condition. Document the specific residual effect, such as scar sensitivity, a granuloma, or pain on weight bearing. Vague wording like “doing okay” does not support sequela coding.
4. External cause code for the original injury. Chapter 19 instructs a secondary Chapter 20 code for the cause of injury, such as W45.8XXS for an object entering through skin. Section I.C.20 has no national mandate, but many payers and states require one.

A clean claim requirements checklist for sequela encounters lets coders confirm all four elements before submission, instead of rebuilding the note after a denial.

Which CPT codes are paired with S90.451S?

The CPT codes submitted alongside S90.451S depend on what the provider does at the sequela visit. Common pairings span evaluation and rehabilitation services across podiatry and physical therapy settings. A podiatry visit for scar pain might bill as 99213, while manual therapy for scar stiffness bills as 97140.

CPT 97001, the old PT evaluation code, was deleted in 2017. Bill a new PT episode with 97161, 97162, or 97163 according to the documented complexity.

Payer rules and pre-authorization for S90.451S claims

Medicare does not typically require prior authorization for an office-based evaluation of a healed toe injury. Medical necessity documentation must still align with the local coverage determination (LCD) for the service billed.

Commercial payers vary considerably, and four rules come up most often:

• Medical necessity threshold. Most commercial payers require the sequela to impair function or cause clinically significant symptoms. Mild residual tenderness without functional limitation is often denied as not medically necessary.
• Prior authorization. Physical therapy billed alongside S90.451S may need prior authorization from some commercial plans. Verify at scheduling, not at claim submission.
• Documentation requests. Payers often send additional documentation requests (ADRs) on sequela claims. They ask for the original injury records and the rationale linking them to the current visit.
• Timely filing limits. Filing windows differ by payer. Confirm the window before billing a delayed sequela encounter.

Check the CMS ICD-10 codes page and your MAC’s LCDs directly when Medicare requirements are unclear, since LCD policies differ by region.

Common claim denial reasons for S90.451S and how to fix them

Most denials on ICD-10 Code S90.451S fall into four categories. Denial management workflows catch them before the claim reaches the payer, which saves a round of rework.

Match the reason code on each EOB against a list of medical billing denial codes to see which root cause to fix first.

ICD-10-CM vs ICD-11: will S90.451S change?

S90.451S remains valid and billable under ICD-10-CM in FY2026. The United States has not set a transition date to ICD-11, and the CDC/NCHS ICD-10-CM tool remains the authoritative reference for current US billing.

ICD-11 uses a different code architecture, so S90.451S will not have a simple one-to-one equivalent when the transition comes. The CMS ICD-10 codes page publishes each annual update, and any change to this code would appear there first.

How Pabau supports sequela coding for S90.451S

Coding a sequela visit correctly depends on the clinician seeing the original injury record. Without it, notes skip the causal link and claims go out with the wrong seventh character.

Pabau, the practice management and billing platform we build, keeps clinical notes, diagnosis codes, and invoices in one patient record. Your coder can read the original removal note before choosing the seventh character.

Pabau’s claims management software submits claims electronically through Claim.MD, its US clearinghouse partner. Claim validation checks each claim for missing or invalid details before it leaves the practice. A wrong field gets fixed before a payer ever sees it.

When a payer wants prior authorization for therapy on a sequela, Pabau stores it as a case attached to the booking. The authorization code then follows the appointment through to the claim.

Tired of sequela claim rejections?

Pabau connects clinical notes, claim validation, and electronic claim submission in one place, so sequela encounters like S90.451S go out with the right code.

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Conclusion

S90.451S is a narrow code, and most errors come from confusing it with its neighbors. It covers a healed superficial foreign body of the right great toe, not an abrasion, not the left side, and not an injury still healing.

Get the injury type, laterality, and seventh character right, and document the link to the original injury. The claim then has what a payer needs to pay it. To see how Pabau keeps those details attached to each claim, book a demo.

Continue your research

Need a medical billing compliance framework for sequela claims? Medical billing compliance covers the documentation standards that keep sequela encounters audit-ready.

Want to understand the full claims submission process? How a medical claims clearinghouse works explains how electronic claim routing catches code errors before payer adjudication.

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