Is L23 a billable ICD-10-CM code?

No. L23 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does L23 sit in the tabular list?

Diseases of the skin and subcutaneous tissue (L00-L99), in the block Dermatitis and eczema (L20-L30).

What cannot be coded together with L23?

L23 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

L23

L23 — Allergic contact dermatitis

Non-billable headerICD-10-CM

L23 is a non-billable header ICD-10-CM code for allergic contact dermatitis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

allergy NOS (T78.40)
contact dermatitis NOS (L25.9)
dermatitis NOS (L30.9)

Excludes2 — not included here, but may coexist

The excluded condition is not part of this code, but a patient can have both. You may code both.

dermatitis due to substances taken internally (L27.-)
dermatitis of eyelid (H01.1-)
diaper dermatitis (L22)
eczema of external ear (H60.5-)
irritant contact dermatitis (L24.-)
perioral dermatitis (L71.0)
radiation-related disorders of the skin and subcutaneous tissue (L55-L59)

Other codes that can never be billed with L23

These codes carry an Excludes1 note pointing at L23. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading L23 alone.

L25Unspecified contact dermatitis
L50Urticaria
L53Other erythematous conditions
T61Toxic effect of noxious substances eaten as seafood
T62Toxic effect of other noxious substances eaten as food
T78.4Other and unspecified allergy

Risk adjustment

L23 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead L23

10 child codes. Green means billable.

Questions about L23

Is L23 a billable ICD-10-CM code?: No. L23 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does L23 sit in the tabular list?: Diseases of the skin and subcutaneous tissue (L00-L99), in the block Dermatitis and eczema (L20-L30).
What cannot be coded together with L23?: L23 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.