Dermatology Coding Alert

Warning: These little-known terms may show up in your doctor's documentation

For dermatologists treating the skin of a patient's foot, one of the most commonly coded diagnoses is corns (and calluses). The condition has a slew of confusing names that may be hard to find -- or may not even be in your coding book -- and could quickly derail your claims.
 
Deciphering all of the corn and callus terminology can be especially difficult if you work for several physicians and each one has his own way of naming the same thing, or if you've recently started working at another practice. But you no longer have to be in the dark over a callus-related term that comes your way.

Familiarize Yourself With the Jargon

You may recognize the word "clavus," since the ICD-9 corn/callus code (700) names it up front. But here are a few more related words that many dermatologists use interchangeably in their notes that you should keep in mind:

 • Clavi (the word for more than one "clavus")
 • Keratosis
 • Keratoma
 • Hyperkeratosis
 • Intractable plantar keratosis (may be abbreviated as "IPK")
 • Heloma
 • Callosity
 • Tyloma
 • Tylosis
 • Durum (this term refers to "heloma durum," which is considered a "hard corn").

Watch out: "Tylosis" could lead you down the wrong coding path if you're not careful. The ICD-9 index in the front of the coding book leads you to several options, such as 757.39 (Other specified amomalies of skin; other; includes accessory skin tags, congenital; congenital scar; epidermolysis bullosa; keratoderma [congenital]), and this is the wrong path for a basic corn or callus, says Linda S. Templeton, CPC, coding consultant for The Rybar Group Inc. in Fenton, Mich. Your best bet when you encounter this term in the documentation is to ask the dermatologist to clarify the condition.

Master the Definitions

If you're still unsure about your dermatologist's everyday description of these common conditions, learning the definitions of "corn" and "callus" will help.

 • A corn is a small, horny area of the skin caused by local pressure (e.g., a shoe or hosiery) irritating the tissue over a bony prominence.
 
Corns usually occur on a toe, where they form "hard corns," says Sherry Wilkerson, RHIT, CCS, CCS-P, manager of coding and compliance for CHAN Healthcare Auditors in St. Louis. "Between the toes, pressure can form a soft corn of macerated skin, which often yellows," she says.

 • A callus is localized thickening and enlargement of the horny layer of the skin due to pressure or friction. Generally, calluses as well as corns can cause pain, and soft-tissue inflammation may occur around the base of the lesion.
 
Knowing these definitions is also helpful if you plan to ask the dermatologist for clarification.
 
Example: You're struggling with how to code a patient diagnosis that describes a "keratosis" of the bottom of the great toe and the heel. You've learned the synonyms for corns/calluses and remember that this is another name for a callus, but you notice that another nearby code has the same word in its descriptor: 701.1 (Keratoderma, acquired; Keratosis [blennorrhagica]).
 
You ask the dermatologist for more details about the patient's condition so you can code it properly, and he describes a basic thickening of the skin because of bad shoes. Referring back to the definitions, now you know that it's just a callus and you can code it as 700.
 
If the condition were keratosis blennorrhagica, the dermatologist would have described a scaly rash that is associated with Reiter's syndrome, and this would tell you to code something other than 700, which is for a mere callus.
 
But if a diagnosis brings you to the 701.x series (Other hypertrophic and atrophic conditions of skin), pay special attention to the definitions under each code, Templeton says.
 
The definitions can help you verify whether the doctor is using the corn/callus term as a synonym or for a more specific description of the condition.