Eczema and Atopic Dermatitis ICD-10-CM codes

ICD-10-CM treats eczema and dermatitis as synonyms, so the code depends on the type documented rather than the word used. Atopic dermatitis goes to L20: L20.9 when unspecified, L20.82 for flexural eczema, L20.83 for infantile eczema, L20.84 for intrinsic (allergic) eczema, and L20.81 for atopic neurodermatitis. Eczema or dermatitis with no type stated indexes to L30.9 (dermatitis, unspecified), not to L20.9; assign L20.9 only when the provider documents atopic dermatitis.

Other named patterns have their own 4th characters in L30: L30.0 nummular (discoid) dermatitis, L30.1 dyshidrosis or pompholyx, L30.3 infective dermatitis, and L30.4 intertrigo. Seborrheic dermatitis is category L21 (L21.9 unspecified, L21.0 cradle cap). Diaper dermatitis is L22. Lichen simplex chronicus from chronic scratching is L28.0, and pruritus without a rash is L29.9.

Contact dermatitis is excluded from L20 and L30 and is coded to L23 to L25 by mechanism and agent. A rash without a diagnosis, for example a visit where the provider documents only rash, is the symptom code R21 in chapter 18, not a dermatitis code. Add Z91.0- allergy status codes when relevant, and Z79.899 or Z79.620 for long-term systemic or biologic therapy.