Ophthalmology and Optometry Coding Alert

Remember to pay attention to code notes.

Conjunctivitis, often called “pink eye,” is a frequently reported diagnosis across primary care, pediatrics, urgent care, and ophthalmology practices. The condition can be the result of viral or bacterial infections, allergies, or irritants. Symptoms include redness and swelling of the conjunctiva, discharge and crusting around the eyelids, itching, burning, blurred vision, and sensitivity to light.

Continue reading to learn more about the condition and how to identify the correct ICD-10-CM codes.

Consider This Conjunctivitis Overview

Viral conjunctivitis typically resolves on its own within one or two weeks, although infections caused by the herpes or zoster viruses may require antiviral eye drops. Bacterial infections are often treated with antibacterial eye drops. Allergic conjunctivitis may also be treated with drops to relieve symptoms.

Allergic conjunctivitis includes giant papillary conjunctivitis (GPC), an inflammation caused by an allergic reaction to contact lenses and a common complication in contact lens users. Vernal conjunctivitis is caused by an allergic reaction to pollen.

Conjunctivitis is diagnosed based on clinical presentation and sometimes laboratory cultures to identify the organism causing the infection. Although clinically common, conjunctivitis can be challenging to code correctly due to variations in etiology, acuity, and laterality. Selecting the correct ICD-10-CM code ensures accurate reporting, coding compliance, and maximum reimbursement.

Understand ICD-10-CM Classification for Conjunctivitis

ICD-10-CM classifies conjunctivitis based on the cause, not only anatomical location. As a result, conjunctivitis is primarily reported using codes from two different chapters, depending on the etiology:

• Chapter 1: Certain Infectious and Parasitic Diseases: Use the B30.- (Viral conjunctivitis) code category when the physician documents a viral conjunctivitis diagnosis.

• Chapter 7: Diseases of the Eye and Adnexa: Look to the H10.- (Conjunctivitis) code category for nonviral conjunctivitis diagnoses.

There are a few exceptions to the guidance above. Code conjunctivitis due to chlamydia to A74.0 (Chlamydial conjunctivitis). When the conjunctivitis is documented as occurring due to trachoma, use A71.1 (Active stage of trachoma). Code conjunctivitis in newborns in the perinatal period (before birth to 28 days) with P39.1 (Neonatal conjunctivitis and dacryocystitis).

Verify Viral Conjunctivitis Codes

When the provider documents conjunctivitis as viral, coders must assign a code from the B30.- category, except for infections caused by the herpes or zoster viruses. The Excludes1 note for B30.- directs you to use different codes for these infections, such as B00.5- (Herpesviral ocular disease) for herpesviral (or herpes simplex) ocular disease and B02.3- (Zoster ocular disease) for ocular zoster.

The ICD-10-CM codes for viral conjunctivitis are as follows:

• B30.0 (Keratoconjunctivitis due to adenovirus)
• B30.1 (Conjunctivitis due to adenovirus)
• B30.2 (Viral pharyngoconjunctivitis)
• B30.3 (Acute epidemic hemorrhagic conjunctivitis (enteroviral))
• B30.8 (Other viral conjunctivitis)
• B30.9 (Viral conjunctivitis, unspecified)

Know How to Code Nonviral Conjunctivitis

Code bacterial, allergic, toxic, chronic, or unspecified conjunctivitis using the H10.- category in Chapter 7. You should also note that there is an Excludes1 note for this category, which lists H16.2- (Keratoconjunctivitis).

Nonviral conjunctivitis uses the following codes based on type and chronicity:

• H10.0- (Mucopurulent conjunctivitis)
• H10.1- (Acute atopic conjunctivitis)
• H10.2- (Other acute conjunctivitis)
• H10.3- (Unspecified acute conjunctivitis)
• H10.4- (Chronic conjunctivitis)
• H10.5- (Blepharoconjunctivitis)
• H10.8- (Other conjunctivitis)
• H10.9- (Unspecified conjunctivitis)

Code H10.3- also features an Excludes1 note that lists P93.1.

Remember: Excludes1 notes instruct you to not code two codes at the same time. An Excludes1 note is used “when two conditions cannot occur together,” according to the ICD-10-CM Official Guidelines, Section I.A.12.a.

Each subcategory has additional characters for further specificity and laterality; for example:

• H10.011 (Acute follicular conjunctivitis, right eye)
• H10.022 (Other mucopurulent conjunctivitis, left eye)
• H10.33 (Unspecified acute conjunctivitis, bilateral)

Recognize Documentation Essentials

To support accurate ICD-10-CM coding, your optometrist’s or ophthalmologist’s documentation should include:

• Etiology: Is the patient experiencing a viral, bacterial, allergic, or toxic infection?
• Type: Is the infection follicular, papillary, or an organism?
• Acuity: Is it an acute or chronic infection?
• Laterality: Is the left or right eye infected? Or are both eyes infected?
• Special circumstances: Was the patient exposed to chemicals? Does the patient have neonatal status?

Avoid Common Coding Errors and Maintain Best Practices

Common errors in coding conjunctivitis include reporting H10.- codes for viral conjunctivitis, missing required laterality characters, confusing acute and chronic diagnoses, using unspecified codes unnecessarily, and failing to recognize neonatal exclusions.

To avoid these pitfalls, try some of these best practices:

• Query the provider if it is unclear whether the conjunctivitis is acute, chronic, viral, bacterial, or allergic. Symptoms and presentation may overlap between the different types, so it is important not to make assumptions if there is not enough information to select an appropriate code.

• Avoid unspecified codes when documentation supports greater specificity and when laterality is noted.

• Use P39.1 when a newborn has conjunctivitis due to contact with bacteria during their birth.

• Code infections due to chlamydia as A74.0 and trachoma as A71.1.

You should also pay attention to and follow the ICD-10-CM instructions and notes for correct code selection and sequencing, such as:

• H10.2- specifies to report a code from the T51-T65 subcategory to identify chemical and intent
• H10.81- features an Excludes1 note for H11.15- (Pinguecula)
• H10.82- instructs you to code L71.- (Rosacea) first for an underlying rosacea dermatitis

Conclusion

Correct coding for conjunctivitis requires more than identifying eye involvement; it demands careful review of documentation for etiology, acuity, and laterality. Understanding when to apply B30.- versus H10.- codes is critical to accurate ICD-10-CM reporting. By following ICD-10-CM guidelines, you can reduce errors, improve claim outcomes, and support high-quality clinical data.

Donna Cuervo, MBA, CPC, CCC, CPMA, CDEO, Contributing Writer