Valid for Submission
S90.421D is a billable diagnosis code used to specify a medical diagnosis of blister (nonthermal), right great toe, subsequent encounter. The code S90.421D is valid during the fiscal year 2021 from October 01, 2020 through September 30, 2021 for the submission of HIPAA-covered transactions. The code is exempt from present on admission (POA) reporting for inpatient admissions to general acute care hospitals.
S90.421D is a subsequent encounter code, includes a 7th character and should be used after the patient has completed active treatment for a condition like blister (nonthermal) right great toe. According to ICD-10-CM Guidelines a "subsequent encounter" occurs when the patient is receiving routine care for the condition during the healing or recovery phase of treatment. Subsequent diagnosis codes are appropriate during the recovery phase, no matter how many times the patient has seen the provider for this condition. If the provider needs to adjust the patient's care plan due to a setback or other complication, the encounter becomes active again.
Diagnostic Related Groups - MS-DRG Mapping
Present on Admission (POA)
Convert S90.421D to ICD-9 Code
The General Equivalency Mapping (GEM) crosswalk indicates an approximate mapping between the ICD-10 code S90.421D its ICD-9 equivalent. The approximate mapping means there is not an exact match between the ICD-10 code and the ICD-9 code and the mapped code is not a precise representation of the original code.
Information for Patients
Also called: Bulla, Vesicle
What are blisters?
Blisters are fluid-filled sacs on the outer layer of your skin. They form because of rubbing, heat, or diseases of the skin. They are most common on your hands and feet.
Other names for blisters are vesicles (usually for smaller blisters) and bulla (for larger blisters).
What causes blisters?
Blisters often happen when there is friction - rubbing or pressure - on one spot. For example, if your shoes don't fit quite right and they keep rubbing part of your foot. Or if you don't wear gloves when you rake leaves and the handle keeps rubbing against your hand. Other causes of blisters include
- Allergic reactions
- Poison ivy, oak, and sumac
- Autoimmune diseases such as pemphigus
- Epidermolysis bullosa, an illness that causes the skin to be fragile
- Viral infections such as varicella zoster (which causes chickenpox and shingles) and herpes simplex (which causes cold sores)
- Skin infections including impetigo
What are the treatments for blisters?
Blisters will usually heal on their own. The skin over the blister helps keep out infections. You can put a bandage on the blister to keep it clean. Make sure that there is no more rubbing or friction on the blister.
You should contact your health care provider if
- The blister looks infected - if it is draining pus, or the area around the blister is red, swollen, warm, or very painful
- You have a fever
- You have several blisters, especially if you cannot figure out what is causing them
- You have health problems such as circulation problems or diabetes
Normally you don't want to drain a blister, because of the risk of infection. But if a blister is large, painful, or looks like it will pop on its own, you can drain the fluid.
Can blisters be prevented?
There are some things you can do to prevent friction blisters:
- Make sure that your shoes fit properly
- Always wear socks with your shoes, and make sure that the socks fit well. You may want to wear socks that are acrylic or nylon, so they keep moisture away from your feet.
- Wear gloves or protective gear on your hands when you use any tools or sports equipment that cause friction.
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