L51.9
Erythema multiforme, unspecified
Billable FY2026 2025-10-01 → 2026-09-30
This is the unspecified option. 5 more
specific codes sit alongside it. Worth
checking whether the documentation supports one of them.
Exclusions 14 never code together
L00-L99chapter
Excludes2
- certain conditions originating in the perinatal period (P04-P96)P04-P96
- certain infectious and parasitic diseases (A00-B99)A00-B99
- complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
- endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
- lipomelanotic reticulosis (I89.8)I89.8
- neoplasms (C00-D49)C00-D49
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94
- systemic connective tissue disorders (M30-M36)M30-M36
- viral warts (B07.-)B07.-
Excludes1 — never code together. The excluded condition and this one are mutually exclusive.
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 18
L51code
Use additional code
- code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)T36-T50
- code to identify associated manifestations, such as:
- arthropathy associated with dermatological disorders (M14.8-)M14.8-
- conjunctival edema (H11.42)H11.42
- conjunctivitis (H10.22-)H10.22-
- corneal scars and opacities (H17.-)H17.-
- corneal ulcer (H16.0-)H16.0-
- edema of eyelid (H02.84-)H02.84-
- inflammation of eyelid (H01.8-)H01.8-
- keratoconjunctivitis sicca (H16.22-)H16.22-
- mechanical lagophthalmos (H02.22-)H02.22-
- stomatitis (K12.-)K12.-
- symblepharon (H11.23-)H11.23-
- code to identify percentage of skin exfoliation (L49.-)L49.-
L51.9code
Inclusion terms
- Erythema iris
- Erythema multiforme major NOS
- Erythema multiforme minor NOS
- Herpes iris
Index entries leading here 4
- Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute) M19.90
- in (due to)
- erythema
- multiforme L51.9
- erythema
- in (due to)
- Arthropathy M12.9
- in (due to)
- erythema
- multiforme L51.9
- erythema
- in (due to)
- Erythema, erythematous (infectional) (inflammation) L53.9
- Herpes, herpesvirus, herpetic B00.9
- iris (vesicular erythema multiforme) L51.9
Alongside this code 5 same parent — L51
Medications 1
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.