2025 ICD-10-CM code W55

Contact with other mammals (excluding marine mammals, dogs, and rodents). This includes contact with their saliva, feces, or urine.

Code W55 is a secondary code used to indicate the external cause of an injury or condition. It should never be used as the primary diagnosis. The primary diagnosis should describe the nature of the injury or condition itself (e.g., laceration, infection, allergic reaction).Refer to the ICD-10-CM Official Guidelines for Coding and Reporting for specific instructions on using external cause codes.

W55 can be used with 7th character extensions to provide more information about the encounter (A = initial encounter, D = subsequent encounter, S = sequela).

The medical necessity for using W55 is to provide additional information about the cause of the injury or condition. It helps to explain the circumstances surrounding the event and supports the primary diagnosis. This information is important for statistical analysis, public health reporting, and insurance claims processing.

The physician's responsibility is to document the nature of the injury resulting from contact with the mammal, as W55 only indicates the external cause and not the diagnosis.This requires specifying the type of injury (e.g., laceration, abrasion, infection) and the affected body part. The physician should also document any related complications and treatments provided.

In simple words: Injury or condition caused by contact with a mammal other than a marine mammal, dog, or rodent.This could include contact with the animal's saliva, feces, or urine.

Contact with other mammals (excluding marine mammals, dogs, and rodents). This includes contact with their saliva, feces, or urine.

Example 1: A patient presents with a rash after contact with a horse. The physician diagnoses contact dermatitis and documents the cause as contact with a horse. W55 is used as a secondary code to indicate the external cause, along with the primary code for contact dermatitis., A farm worker develops an infection after being exposed to cow feces.The physician diagnoses the infection and documents the source.W55 is used as a secondary code, along with the primary code for the specific infection., A child develops allergies after prolonged contact with a rabbit. The physician diagnoses an allergic reaction and notes the exposure to the rabbit. Code W55 is used to indicate the external cause, and a code for the specific allergy is used as the primary diagnosis.

Documentation should clearly state the type of injury resulting from the contact with the mammal (e.g., scratch, bite, allergic reaction, infection), the specific mammal involved (e.g., horse, cow, rabbit), and the affected body part. Documentation of the encounter should also include the patient's symptoms, examination findings, treatment provided, and any associated complications.

** Excludes1: animal being ridden (transport accidents), bitten or struck by dog (W54), bitten or struck by rodent (W53.-), contact with marine mammals (W56.-), toxic effect of contact with venomous animals and plants (T63.-).

  • Specialties:The specialties that commonly use this code include: Primary Care, Emergency Medicine, Urgent Care, Occupational Medicine, Allergy and Immunology, Infectious Disease.
  • Place of Service:This code can be applied in various places of service, including "Office", "Home", "Inpatient Hospital", "On Campus-Outpatient Hospital", "Emergency Room - Hospital", "Urgent Care Facility", "Rural Health Clinic", and others, depending on where the patient received treatment for the condition caused by contact with the mammal.
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