ICD-10 Reminder Series: Chapter 1.C. 12 Diseases of Skin & Subcutaneous Tissue

In this blog we will be going over ICD-10-CM guidelines for correct code assignment for Diseases of the Skin and Subcutaneous Tissue, which are found in Chapter 12 of ICD-10-CM. We’ve got a lot to cover, so let’s jump right in…

Pressure Ulcer Stages: ICD-10-CM codes from category L89 classifies Pressure Ulcer Stages based on severity, which is designated by stages 1 to 4, unspecified stage, and unstageable. The fourth character denotes anatomy, while the fifth character denotes specific site, and the sixth character denotes depth of ulcer.

Unstageable Pressure Ulcers (L89. —0): Assignment of codes should be based on clinical documentation. These codes are used for pressure ulcers whose stage cannot be determined clinically and are documented as deep tissue injury, but not due to trauma. Remember, no code should be assigned if the patient is admitted with a healed pressure ulcer. However, if the patient is admitted with a healing pressure ulcer, the appropriate pressure ulcer stage should be assigned based on medical record documentation.

When the stage of the pressure ulcer is not documented, the appropriate ICD-10-CM code for unspecified stage (L89. –9) should be assigned. If the documentation is not clear whether pressure ulcer is current or being treated, you should ask the provider. If an ulcer is present on admission, but healed at the time of discharge, a code for the site and stage of pressure ulcer should be assigned.

If pressure ulcer progresses from one stage to a higher stage, two separate codes should be assigned: one for the site and stage of the ulcer on admission, and a second code for the same site, and the highest stage should be assigned.

Examples:

  1. A patient was seen for a rash that developed on the patient’s trunk and upper extremities over the last 4 days. The patient was diagnosed with hypertension seven days ago and started taking Ramipril 10mg daily. The physician determined the rash was dermatitis due to Ramipril. The appropriate ICD-10-CM codes for this patient, as per ICD-10-CM guidelines, are L27.1, T46.4X5A, and I10.
  2. Atherosclerosis of the right ankle with non-healing ulcer with breakdown of skin. The appropriate ICD-10-CM codes for this patient, as per ICD-10-CM guidelines, are I70.233 and L97.311
  3. Patient comes in with bed sores on the left buttock. After the examination, the physician documents a decubitus ulcer of the left buttock, stage II. The appropriate ICD-10-CM code for this patient, as per ICD-10-CM guidelines, is L89.322

Non-Pressure Chronic Ulcers: No code should be assigned if the patient is admitted with healed non-pressure ulcer. If the ulcer is healing, an appropriate code should be assigned based on medical record documentation. If the severity of the non-pressure ulcer is unknown, then the appropriate code for unspecified severity should be assigned. If documentation is not clear whether the non-pressure ulcer is current or being treated, ask the provider. If an ulcer is present on admission, but healed at the time of discharge, then a code for the site and severity, at the time of admission, should be assigned.

And remember, if a non-pressure ulcer progresses from one stage to a higher stage, two separate codes should be assigned: one for the site and stage of ulcer on admission and second code for the same site and the highest severity should be assigned.

Example: A patient is treated for a severe non-healing ulcer of the right midfoot and heel with bone necrosis due to diabetes mellitus. The appropriate ICD-10-CM codes for this patient, as per ICD-10-CM guidelines, are E086.621 and L97.413.

Gangrene at the Site of Ulcer: The gangrene should be coded first, followed by the code for the ulcer. For example, the patient has a gangrenous pressure ulcer of the right hip and sacrum. The physician assessment indicated a stage-two pressure ulcer of sacrum, with a stage three decubitus ulcer of the right hip. The appropriate ICD-10-CM codes for this patient, as per ICD-10-CM guidelines, are I96, L89.213, L89.152.

A secondary external cause code identifying the exposure’s source should be used when reporting categories L56, Other Acute Skin Changes due to Ultraviolet Radiation, and L57, Skin Changes Due to Chronic Exposure to Non-ionizing Radiation.

Example: The patient presents with solar keratoses on their face due to overexposure in the tanning bed. The appropriate ICD-10-CM codes for this patient, as per ICD-10-CM guidelines, are L57.0, W89.1, Y92.039.

The place of occurrence codes for home is sub-divided to include apartment, boarding home, single family residence, institution, nursing home, prison, reform school dormitory, and mobile home. These categories are further divided to include areas of the home, including the bathroom, bedroom, driveway, garden, kitchen, swimming pool, etc.

Intraoperative and post-procedural complications of the skin and subcutaneous tissue (L76) are divided into fourth and fifth characters. The fourth character describes complications and conditions following surgery, for example: hemorrhage and hematoma. Meanwhile, the fifth character further specifies the complication, for example: Intraoperative hemorrhage and hematoma of skin and subcutaneous tissue complicating a dermatologic procedure – L76.01 and Intraoperative hemorrhage and hematoma of skin and subcutaneous tissue complicating other procedure – L76.02.

Some ICD-10-CM codes for the skin have been expanded further to include notes directing the use of an additional code to identify organism (B95–B97), code first (T36–T65) to identify drug or substance, underlying disease and any associated disease.

For example: L00-L08 Infections of the skin and subcutaneous tissue, use additional code (B95–B97) to identify infectious agent, Allergic contact dermatitis – L23 Code first (T36–T65) to identify drug or substance.

In conclusion, the code assignment for Diseases of Skin and Subcutaneous Tissue is complex. But with proper documentation and the use of set guidelines for assigning the correct ICD-10-CM code, you can remove some of the inherent complexity while improving your coding accuracy.

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