W55.1

Contact with horse

FY2027Chapter 20: External causes of morbidity/W50–W64 Exposure to animate mechanical forces

Non-billable headerNot valid on its own. Use one of the more specific codes under it.

W55.1 is a non-billable ICD-10-CM code header for contact with horse. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are W55.11 Bitten by horse, W55.12 Struck by horse and W55.19 Other contact with horse. Its coding notes include 5 Excludes1 entries.

7th characters

Every code below needs one of these (defined at W55).

The appropriate 7th character is to be added to each code from category W55

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Guidelines tip

From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.

An external cause code is never a principal or first-listed diagnosis. Its 7th character is assigned for each encounter and should match the injury or condition code.

Guidelines I.C.20.a.2; I.C.20.a.6External cause codesRead the official text

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Inherited from W55 Contact with other mammals
  • animal being ridden- see transport accidents
  • bitten or struck by dog (W54)
  • bitten or struck by rodent (W53.-)
  • contact with marine mammals (W56.-)
Also from chapter/block level (1 note)
Inherited from W50–W64 Exposure to animate mechanical forces
  • Toxic effect of contact with venomous animals and plants (T63.-)

Includes

Further defines or gives examples of the content of the category.

Inherited from W55 Contact with other mammals
  • contact with saliva, feces or urine of mammal

Notes

Also from chapter/block level (1 note)
Inherited from Chapter 20 External causes of morbidity
  • This chapter permits the classification of environmental events and circumstances as the cause of injury, and other adverse effects. Where a code from this section is applicable, it is intended that it shall be used secondary to a code from another chapter of the Classification indicating the nature of the condition. Most often, the condition will be classifiable to Chapter 19, Injury, poisoning and certain other consequences of external causes (S00-T88). Other conditions that may be stated to be due to external causes are classified in Chapters I to XVIII. For these conditions, codes from Chapter 20 should be used to provide additional information as to the cause of the condition.

More specific codes under W55.1 3