Black Blisters on Heels: Diabetes and Vascular Issues

There is a black lump in the blister on the heel?

My father has undergone coronary angioplasty and has poorly controlled diabetes, with pre-meal blood sugar levels ranging from 250 to 350.
Currently, he is taking insulin injections in the morning and evening.
Two days ago, he developed two blisters on his right heel, one about the size of a 50 NT dollar coin, and the other a small one that appears dark (I initially thought it was a bruise).
Today, a bruise-like area on his left heel is starting to form a blister (it is slightly raised and uneven).
At first, I thought he might have bumped into something, but he insists he did not.
A neighbor mentioned that his wife had a similar issue, and the doctor said it was due to lower limb vascular occlusion, which is common in diabetic patients.

Could this be due to vascular occlusion, or could there be other reasons? My father is on anticoagulant medication; could this be a side effect of the medication? Which specialist should I consult? Should I go to a diabetes clinic, a surgical department, or a cardiology department? Thank you.

Xiao Miao, 30~39 year old female. Ask Date: 2013/07/21

Dr. Chen Qingbin reply Internal Medicine

Hello, diabetes patients are prone to vascular sclerosis and obstruction, and taking anticoagulants can easily lead to subcutaneous bruising.
It is best to return to the original hospital for a consultation, where a physician can conduct a detailed examination to determine if a referral to a related specialty for further treatment is necessary.

Reply Date: 2013/07/21

More Info

The symptoms you describe regarding your father's condition, particularly the appearance of blisters and dark spots on his heels, are concerning and warrant careful consideration. Given his history of poorly controlled diabetes and previous cardiac interventions, there are several potential underlying causes for these symptoms, including vascular issues, diabetic complications, and possible medication side effects.

Potential Causes
1. Diabetic Dermopathy: This is a common skin condition in individuals with diabetes, characterized by light brown, scaly patches on the skin. While it typically does not present as blisters, it can lead to skin changes that may resemble what you are observing.

2. Vascular Complications: Diabetes can lead to peripheral vascular disease (PVD), which affects blood flow to the extremities. Poor circulation can result in skin changes, including the formation of blisters or ulcers, particularly on the feet and heels. The fact that your father has a history of heart disease and has undergone stenting suggests that he may have systemic vascular issues, which could contribute to these symptoms.

3. Pressure Ulcers: If your father has reduced sensation in his feet due to diabetic neuropathy, he may not be aware of pressure points that can lead to skin breakdown and blister formation. These can occur without any noticeable trauma.

4. Medication Side Effects: If your father is on anticoagulant therapy, it is possible that this could contribute to bruising or bleeding under the skin, leading to the appearance of dark spots or blisters. Anticoagulants can increase the risk of bleeding, especially in areas where the skin is fragile.

5. Infection: Blisters can also be a sign of infection, particularly in individuals with diabetes, who are at higher risk for skin infections. If the blisters are filled with fluid and are painful, this could indicate an infection that requires prompt medical attention.

Recommended Actions
Given the complexity of your father's symptoms and his medical history, it is crucial to seek medical attention promptly. Here are the steps you should consider:
1. Consult a Healthcare Provider: It would be advisable to start with a visit to a diabetes clinic or an endocrinologist who specializes in diabetes management. They can assess his blood sugar control and its impact on his skin and vascular health.

2. Dermatology Referral: If the skin lesions are persistent or worsening, a referral to a dermatologist may be necessary. They can provide a more detailed examination and determine if the lesions are related to diabetes or another skin condition.

3. Vascular Assessment: Given the potential for vascular issues, a consultation with a vascular surgeon or a cardiologist may also be warranted. They can evaluate blood flow to the lower extremities and determine if there are any blockages or circulatory problems.

4. Wound Care: If the blisters or dark spots are open or at risk of becoming infected, proper wound care is essential. This may include keeping the area clean and protected, and possibly using topical treatments as advised by a healthcare professional.

Conclusion
In summary, the symptoms your father is experiencing could be related to a combination of factors associated with diabetes, including vascular complications and potential medication side effects. It is essential to address these symptoms promptly to prevent further complications. Regular monitoring of blood glucose levels and maintaining good diabetes management are crucial in preventing such issues. Please ensure that your father receives a thorough evaluation from the appropriate healthcare professionals to determine the best course of action.

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