2026 ICD-10-CM Diagnosis Code T49.8X5AAdverse effect of other topical agents, initial encounter
T49.8X5A is a billable ICD-10-CM diagnosis code for adverse effect of other topical agents, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 917 through 918. The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Adverse effects of drugs and medicaments, initial encounter.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T49.8X5A.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute phototoxic reaction
- Allergic reaction to cosmetics
- Circulatory topical preparations adverse reaction
- Delayed photoallergic dermatitis
- Gamolenic acid adverse reaction
- Glossitis caused by oil of cinnamon
- Hemorrhoid preparation adverse reaction
- Non-ionic surfactant adverse reaction
- Nonoxinol adverse reaction
- Octoxinol adverse reaction
- Photoallergic contact dermatitis due to sunscreen
- Photoallergic dermatitis
- Phototoxic reaction of skin caused by cosmetic
- Phototoxic reaction of skin caused by fragrance
- Phototoxic reaction to topical chemical
- Phototoxic reaction to topical psoralen therapy
- Phototoxic reaction to topically applied medicament
- Podophyllotoxin adverse reaction
- Urea creams adverse reaction
Coding GuidelinesGuidance
When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug.
The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of topical agents primarily affecting skin and mucous membrane and by ophthalmological, otorhinorlaryngological and dental drugs (T49). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Cosmetics
substances intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance without affecting the body's structure or functions. included in this definition are skin creams, lotions, perfumes, lipsticks, fingernail polishes, eye and facial makeup preparations, permanent waves, hair colors, toothpastes, and deodorants, as well as any material intended for use as a component of a cosmetic product. (u.s. food & drug administration center for food safety & applied nutrition office of cosmetics fact sheet (web page) feb 1995)Hair Preparations
hair grooming, cleansing and modifying products meant for topical application to hair, usually human. they include sprays, bleaches, dyes, conditioners, rinses, shampoos, nutrient lotions, etc.Acidosis, Lactic
acidosis caused by accumulation of lactic acid more rapidly than it can be metabolized. it may occur spontaneously or in association with diseases such as diabetes mellitus; leukemia; or liver failure.Lactic Acid
a normal intermediate in the fermentation (oxidation, metabolism) of sugar. the concentrated form is used internally to prevent gastrointestinal fermentation. (from stedman, 26th ed)Lactobacillales
an order of gram-positive bacteria in the class bacilli, that have the ability to ferment sugars to lactic acid. they are widespread in nature and commonly used to produce fermented foods.Pyruvate Carboxylase Deficiency Disease
an autosomal recessive metabolic disorder caused by absent or decreased pyruvate carboxylase activity, the enzyme that regulates gluconeogenesis, lipogenesis, and neurotransmitter synthesis. clinical manifestations include lactic acidosis, seizures, respiratory distress, marked psychomotor delay, periodic hypoglycemia, and hypotonia. the clinical course may be similar to leigh disease. (from am j hum genet 1998 jun;62(6):1312-9)Pyruvate Dehydrogenase Complex Deficiency Disease
an inherited metabolic disorder caused by deficient enzyme activity in the pyruvate dehydrogenase complex, resulting in deficiency of acetyl coa and reduced synthesis of acetylcholine. two clinical forms are recognized: neonatal and juvenile. the neonatal form is a relatively common cause of lactic acidosis in the first weeks of life and may also feature an erythematous rash. the juvenile form presents with lactic acidosis, alopecia, intermittent ataxia; seizures; and an erythematous rash. (from j inherit metab dis 1996;19(4):452-62) autosomal recessive and x-linked forms are caused by mutations in the genes for the three different enzyme components of this multisubunit pyruvate dehydrogenase complex. one of the mutations at xp22.2-p22.1 in the gene for the e1 alpha component of the complex leads to leigh disease.Podophyllotoxin
a lignan (lignans) found in podophyllin resin from the roots of podophyllum plants. it is a potent spindle poison, toxic if taken internally, and has been used as a cathartic. it is very irritating to skin and mucous membranes, has keratolytic actions, has been used to treat warts and keratoses, and may have antineoplastic properties, as do some of its congeners and derivatives.
Table of Drugs and ChemicalsClinical
Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.
Patient EducationClinical
Drug Reactions
Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions, such as drug interactions, side effects, and allergies.
The full article covers:
- What is a drug interaction?
- What are side effects?
- What are drug allergies?
- How can I stay safe when taking medicines?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T49.8X5A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T49.8X5AOverview
Is T49.8X5A (Adverse effect of other topical agents) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of other topical agents, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T49.8X5A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for adverse effect of other topical agents, such as an emergency visit or first evaluation.
What MS-DRG does T49.8X5A group to?
On inpatient claims, adverse effect of other topical agents, initial encounter maps to MS-DRG 917, 918, with relative weights from 0.8571 to 1.5684 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T49.8X5A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of other topical agents, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
What is the ICD-9 equivalent of T49.8X5A?
Under the General Equivalence Mappings, adverse effect of other topical agents, initial encounter converts to ICD-9-CM 995.29 (adv eff med/biol NEC/NOS) and E946.8 (adv eff skin agent NEC). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
