Look Beyond Lyme Disease for Tick Bite Dx Coding

Look Beyond Lyme Disease for Tick Bite Dx Coding

Proper reporting requires at least two codes for anatomical site and external cause.

With a social distancing order in place, my husband and I have been working from home and allowing ourselves the pleasure of walks with our children during our official afternoon breaks. Usually, the kids stay out and play for a while before coming back into the house. Yesterday, my daughter came in with a tick firmly lodged in the skin of her lower abdomen. This encounter set me thinking about coding for tick bites.

About Ticks

Tick bites are often easy to spot because the tick usually attaches to the skin and may stay there for up to 10 days. They are mostly harmless, causing minor to no physical symptoms. However, there are disease-carrying ticks that can transfer diseases to humans. According to the Centers for Disease Control and Prevention (CDC), tick bites are common from April through September — the warmer months, when they are most active.

Signs and symptoms vary from no reaction to allergic symptoms such as rash, pain, irritation, and itching at the site of the bite. In severe allergy cases, difficulty breathing has been reported. Tick-borne illnesses include Lyme disease and Rocky Mountain spotted fever, as well as the lesser-known Colorado tick fever, human granulocytic anaplasmosis, human babesiosis, tularemia, and human monocytic ehrlichiosis.

Documentation Requirements

To ensure the right code selection, documentation for tick bites should include the site of the bite and the cause of injury, which in this case would be “bite by a tick.” If several bites are present, documentation should include the site of each bite. Documentation should also state if there is infection present at the site of the bite.

Coding Tick Bites

ICD-10-CM classifies bites under Chapter 19: Injury, Poisoning, and Certain Other Consequences of External Causes (S00-T88). Documentation requirements for injuries include the site of injury, as well as the cause. Depending on the payer, a location and activity at the time of injury may also be necessary.

Coding for tick bites requires at least two codes:

1. Code first the location of the bite(s).

In the Alphabetic Index, look up “insect” under Bite(s). You are directed to “see Bite, by site, superficial, insect.” Looking up bite, [site] leads to a five- or six-character S code. When you verify that in the Tabular List, you see a 7th character requirement, so choose which one applies for the episode of care.

Capture codes for all specified sites with bites. Per 2020 ICD-10-CM Official Guidelines for Coding and Reporting, “When coding injuries, assign separate codes for each injury unless a combination code is provided, in which case the combination code is assigned.”

2. Code also the external cause of injury.

In the External Causes Index, look for “bite.” Under Bite, bitten by, a search for “tick” comes up empty, but insect (nonvenomous) leads to W57 Bitten or stung by nonvenomous insect and other nonvenomous arthropods. Following this up in the Tabular List, there is a 7th character requirement, so add placeholders as needed for six characters and choose the episode of care that applies.

Note that the External Causes code can never be first-listed or the only code captured for a tick bite. A note at the beginning of Chapter 19: Injury, Poisoning, and Certain Other Consequences of External Causes (S00-T88) states, “Use secondary code(s) from Chapter 20, External cause of morbidity, to indicate cause of injury.”

Also, Section I.B.19.a of the 2020 ICD-10-CM Official Guidelines states, “The use of external cause of morbidity codes is supplemental to the application of ICD-10-CM codes. External cause of morbidity codes are never to be recorded as a principal diagnosis (first-listed in non-inpatient settings). The appropriate injury code should be sequenced before any external cause codes.”

Now, let’s practice coding a couple of scenarios.

Coding Scenario 1

Documentation: Patient comes in complaining of a tick bite to the right lower abdomen, which happened yesterday. The area was itchy and swollen but has improved. Examination of skin shows a bump on the patient’s lower abdomen, firm to the touch. No pain on palpation, just a bit itchy; looks to be healing. No foreign body is apparent on exam. Patient is to keep the area clean and contact the clinic if any new or worsening symptoms develop.

Diagnosis: Tick bite, right lower abdomen

Coding: S30.861A, W57.XXXA

1. Site: S30.861A Insect bite (nonvenomous) of abdominal wall, initial encounter

2. External cause: W57.XXXA  Bitten or stung by nonvenomous insect and other nonvenomous arthropods, initial encounter

Rationale: In the Alphabetic Index, look up “insect” under Bite. This instructs you to “see Bite, by site, superficial, insect.” Look up Bite, abdomen, abdominal, wall, superficial, insect to locate S30.861. In the Tabular List, you’ll see that this code has a 7th character requirement. Choose the 7th character A (initial encounter for active treatment).

In the External Causes Index, look for “bite.” Bite, bitten by does not list “tick,” but insect (nonvenomous) leads to W57. In the Tabular List, there is a 7th character requirement. Add three Xs as placeholders for the 4th-6th characters and choose the episode of care that applies for the 7th character.

There is no mention of a place of occurrence, so you cannot code this.

Coding Scenario 2

Documentation: Patient presents with a complaint of tick bites five days ago. He has not received any treatment for it. Patient’s wife found and removed a tick attached to patient’s neck the day after he had spent time in the barn on the farm. He had removed one tick from his left pelvis the day before. The neck location has been itching and is painful for the past three days. Patient admits to scratching it with no relief. The bite on his pelvis is diminishing.

He denies any respiratory, joint, or general symptoms. Exam shows a small bump on his left pelvis and an irritated, swollen area on the back of patient’s neck. The skin on the back of the neck looks infected, and there is pain on palpation. Prescription written for a 10-day course of oral antibiotics to treat the infection. Serum labs to be drawn today. He is to follow up in two weeks at the clinic. Will have him in sooner if labs warrant it. Patient is to take medications as prescribed and call office if any other symptoms occur. Tylenol for pain as needed.

Diagnoses: Tick bite, pelvis and infected tick bite, back of neck

Coding: S30.860A, S10.86XA, L08.9, W57.XXXA, Y92.71

1. Sites: S30.860A Insect bite (nonvenomous) of lower back and pelvis, initial encounter; S10.86XA Insect bite of other specified part of neck, initial encounter

2. Infection: L08.9 Local infection of the skin and subcutaneous tissue, unspecified

3. External cause: W57.XXXA

4. Place of occurrence: Y92.71 Barn as the place of occurrence of the external cause

Rationale: For the bite on the patient’s pelvis, look up “insect” under Bite in the Alphabetic Index. This leads you to see Bite, by site, superficial, insect. Look this up to locate S30.860. In the Tabular List, there is a 7th character requirement. Choose the 7th character A.

For the bite on the back of the patient’s neck, look up “insect” under Bite in the Alphabetic Index. This leads you to see Bite, by site, superficial, insect. Look up Bite, neck, specified site NEC, superficial, insect to locate S10.86. In the Tabular List, there is a 7th character requirement. Add one placeholder character X and choose the 7th character A.

There are several entries under neck, but none for back of neck; however, because the provider documented a specific part of the neck (i.e., back of neck), choose the “Not elsewhere classifiable” (NEC) code to indicate location. This abbreviation in the Alphabetic Index represents “other specified.” When a specific code is not available for a condition, the Alphabetic Index directs the coder to the “other specified” code in the Tabular List (Section I.A.6.a.).

The provider’s notes say the bite to the neck is infected, so you’ll code for the infection, as well. In the Alphabetic Index, look up “Infection, skin (local)” to find L08.9. Verify the code in the Tabular List.

In the External Causes Index, look for “bite.” Bite, bitten by does not list “tick,” but insect (nonvenomous) leads to W57. In the Tabular List, there is a 7th character requirement. Add three Xs as placeholders for the 4th-6th characters and choose the episode of care that applies for the 7th character.

In the External Causes Index, look for “farm” under Place of occurrence. Place of occurrence, farm (land under cultivation) (outbuildings), barn leads to Y92.71.


Resources:

Bishop. S, Wright A. MD. Mayo Clinic Q and A: How to remove a tick quickly and correctly.
Mayo Clinic. https://newsnetwork.mayoclinic.org/discussion/be-aware-of-signs-and-symptoms-associated-with-tick-related-diseases. Published Sept. 10, 2010.
Accessed April 16, 2020. 

Centers for Disease Control and Prevention. Ticks.
www.cdc.gov/ticks. Published Nov. 4, 2019. Accessed April 16, 2020

ICD-10-CM Expert. Diagnosis Codes for Providers & Facilities. AAPC. 2020.

Meta N Awuah-Offei
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About Has 1 Posts

Meta N Awuah-Offei, CPC, CPMA, CRC, CEMC, is a coding and auditing professional. She loves learning, teaching, and interacting with other professionals. Awuah-Offei is a trained engineer who switched careers to allow more flexibility for work and family life balance. She is affiliated with the Rolla, Mo., local chapter, which she started with her coworkers.

One Response to “Look Beyond Lyme Disease for Tick Bite Dx Coding”

  1. La Donna C. says:

    I am so very impressed with the workmanship of this person. She is such a hard worker, very pleasant to be around and always open to investigate any and all health concerns that may help in the medical field. She is very trustworthy, honest and a very smart person!!
    Any company would profit from having workers this qualified and hard working in their task force!!

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