ICD 10 Coding Alert

Hint: Anaphylactic shock is a factor in insect bite coding.

It seems to be getting warmer earlier every year, and people have already headed outdoors for springtime activities in many areas.

When this occurs, providers also get an uptick in seasonal issues. Diagnosis coding for these services can get your head spinning if you’re not ready to report when the claim arrives.

Check out these examples of common seasonal presentations, and our expert advice for working out any coding kinks you might have.

Report Rash With L Codes

One of the common presentations you’ll see in warm weather involves patients reporting with a rash after working outdoors. So let’s say a patient presents with a rash that covers their entire left arm. The patient was working in their yard when they noticed a small rash on the left forearm. After 24 hours, the rash spread to cover their arm; it had also started to blister. The provider diagnoses dermatitis due to contact with poison ivy.

ICD-10-CM coding: When a patient has a plant-induced rash, ICD-10-CM does not break it down by plants, so you will use either L23.7 (Allergic contact dermatitis due to plants, except food), L24.7 (Irritant contact dermatitis due to plants, except food), or L25.5 (Unspecified contact dermatitis due to plants, except food).

To determine which code to use, you will need to see if your provider has noted whether the rash is localized to one specific area of the patient’s skin or whether it has spread. “If the rash has spread and is now causing significant issues, such as infections on the skin, then you would use L23.7, the code for allergic contact. Also, if the origin of the rash cannot be assessed, you would use L25.5, the unspecified code,” explains Mary I. Falbo, MBA, CPC, CEO of Millennium Healthcare Consulting Inc. in Lansdale, Pennsylvania.

Get Your Seasonal Allergy Dx Coding in Line

If your practice is in a warmer climate, you might already be fielding a bunch of patients with allergy issues. If you cannot choose the correct diagnosis code for these patients, it could be you that ends up with a headache.

Example: A patient presents with a runny nose, watery eyes, and sneezing. The provider documents hay fever and determines the patient has seasonal allergies and deduces pollen as the allergen.

Diagnosis coding: You can find many allergy-related conditions within the J30.- (Vasomotor and allergic rhinitis) codes. For this scenario, resist the temptation to report J30.2 (Other seasonal allergic rhinitis). Even though the provider documented seasonal allergies, J30.1 (Allergic rhinitis due to pollen) is more appropriate.

While seasonal rhinitis is common in spring, and even summer and early fall, “the typical causes are airborne mold spores, dust mites, or pollens from grass, trees and weeds,” says Melanie Witt, RN, CPC, MA, an independent coding expert based in Guadalupita, New Mexico. A quick look at the alphabetic index will tell you why J30.1 is the better choice.

The ICD-10-CM index entry for hay fever refers you to J30.1. Additionally, “hay fever” is listed as one of the synonyms for J30.1. And finally, “you would report J30.2 if airborne mold spores or dust mites cause the condition; whereas you would report J30.1 for hay fever as the code specifically cites pollen as the cause,” Witt adds.

Insect Bites Could Be Serious Business

For most patients, stings and bites generally cause itching and mild discomfort. But for others, a sting or bite can cause anaphylactic shock, which can range in severity from a rash or hives to a potentially life-threatening closure of the airways.

Bites from mosquitos and ticks can also produce rashes that are symptomatic of other dangerous conditions such as Rocky Mountain spotted fever and Lyme disease.

And the coding can be tricky, as “you need to keep in mind that there are over 350 diagnoses that could relate based on site and care,” says Chelle Johnson, CPMA, CPC, CPCO, CPPM, CEMC, AAPC Fellow, billing/credentialing/auditing/coding coordinator at County of Stanislaus Health Services Agency in Modesto, California.

Diagnosis coding: For rashes caused by nonvenomous insect bites, you’ll first want to code the condition associated with the bite, such as A77.0 (Spotted fever due to Rickettsia rickettsii) for Rocky Mountain spotted fever and A69.2- (Lyme disease) for Lyme disease. Then you will use W57.XXXA (Bitten or stung by nonvenomous insect and other nonvenomous arthropods, initial encounter) for the bite. (Tip: For emergency department [ED] encounters, the appropriate 7th character is nearly always A.)

However, rashes caused by bee stings and other venomous animal or insect bites are coded differently. Again, you’ll code the condition first — in this case, anaphylactic shock using T78.2XXA (Anaphylactic shock, unspecified, initial encounter). Then you will use T63.4- (Toxic effect of venom of other arthropods), adding the appropriate 5th chacacter for the kind of insect and the appropriate 6th character to indicate intentionality (again, the appropriate 7th character is nearly always A for ED encounters). And this time, you will add an encounter code from Z91.03- (Insect allergy status) to indicate the anaphylaxis. These also require a 6th character, so report either Z91.030 (Bee allergy status) or Z91.038 (Other insect allergy status) for the encounter.