How to Determine Whether Foot and Leg Blisters Are Related to Water Retention or Diabetes
Leg and Foot Health Issues
A number of medical patients confuse the symptoms of water retention (also known as fluid retention or edema) with the appearance of chronic diabetic skin blisters. Misunderstandings about the differences between the two conditions can cause undue anxiety in patients and their caregivers.
In simple terms, water retention happens inside the body cavities and tissues to cause swelling of such areas as joints and limbs. In contrast, diabetic blisters occur on the outside surface of the body to cause raised areas filled with liquid.
Disclaimer: The following information is intended to provide a general overview. It should not be used for official diagnosis or substituted for the expertise of a licensed healthcare practitioner. Please see your medical provider for complete diagnosis and treatment.
Foot, leg, and ankle swelling are the painless swelling of the feet and ankles as a common problem, especially among older people.— US National Library of Medicine; Medline Plus, Article 003104
What is Water Retention?
Fluid retention, or edema, and diabetic blisters are different in a number of ways. The first difference is that edema occurs inside body cavities or tissues, while diabetic blisters appear on the skin, outside of the body where you can see them.
Edema does not cause blisters on the skin, but it can cause swelling below the skin layers, inside other tissues and body cavities. This swelling can stretch the skin above the edema and make it look shiny (please see photos above).
Patients can confuse edema with blisters associated with untreated and uncontrolled or poorly controlled blood glucose levels in the chronic varieties of type I and type II diabetes and even hypoglycemia. Pre-diabetes and gestational diabetes are temporary and not likely to produce blisters.
In some cases, a patient might feel it more socially acceptable and less embarrassing to attribute diabetic blisters to "retaining water", but this personal attribution can delay vital treatment. Knowing and accepting the differences between the two conditions is important and supportive family and friends can help the patient accept the correct diagnosis.
The major differences found when comparing edema with diabetic blisters are listed in the table below, with explanations.
Edema Compared With Diabetic Blisters (Bullosis Diabeticorum)
DESCRIPTION: Excess body fluid, often lymph, is trapped inside body tissues or cavities.
DESCRIPTION: Raised areas of liquid-filled skin appear and can be quite large on the lower legs.
USUAL LOCATION: Arms, hands, legs, ankles, and feet. Pulmonary edmea occurs within the lungs.
USUAL LOCATION: Calves, shins, and feet. Can also appear on forearms, hands, and fingers.
USUAL CAUSES: Excessive salt ingestion, pregnancy, PMS, cardiopulmonary issues, vein damage in lower legs, lymphatic system compromise, kidney disease, cirrohsis, some medications, injuries, some cancer surgeries, long airline flights..
SUSPECTED USUAL CAUSES: Diabetics can be at higher risk for foot blisters from shoes, especially in the presence of neuropathy that causes numbness; Ultraviolet radiation exposure; possibly trauma, possibly small blood vessel disease (research is ongoing); insufficient blood glucose regulation (type I and type II diabetes and hypoglycemia).
COMPLICATIONS: Pain, stiffness, diffuclty walking (legs/feet), damage to body tissues, internal tissue scarring, increased risk of infection in affected areas.
COMPLICATIONS: Pain, staphylococcal infection that sometimes leads to amputation, bone infection near blister sites if blisters are recurring, ulceration of blisters.
What are Diabetic Blisters (Bullosis Diabeticorum)?
Infrequently, individuals with diabetes can erupt in blisters on the hands, fingers, lower legs, and feet. Blisters even less frequently may occur elsewhere, like the forearms or thighs.
The blisters look somewhat like second-degree burn blisters and are sometimes large, but they are painless and have no redness around them. They usually heal by themselves, without scars, in about about two to six weeks. The only sure treatment is to bring blood sugar levels under control (Source: diabetes.org/living-with-diabetes/complications/skin-complications.html. Retrieved March 10, 2015).
In some cases in which glucose blood levels are not well controlled, large blisters on the legs may be opened purposely by a patient or opened accidentally by friction from clothing, shoes, or tools. Bacteria enter and the resulting infections are painful and sometimes deadly.
Chronic diabetes can result in a number of skin conditions, described in depth at Skin Complications: American Diabetes Association. Up to 33 percent of people with diabetes will have one of the mentioned skin disorders.
The American Diabetes Association states that the only sure treatment for diabetic blistering is to bring blood sugar levels under control to the advised healthy level.
Embarrassment, Denial, and Effective Treatment
Very large blisters on the lower legs and forearms can present an embarrassment to patients and their families. A temptation exists to explain away blisters as water retention. Various home treatments frequently fail, causing frustration and additional pain. A few patients pop the blisters against the advise of physicians and then suffer infected wounds or ulcerated areas.
An Example of Severe Diabetic Blisters
A former neighbor of mine aged 55, with moderate obesity, suffered a group of blisters along both calves and shins, each blister reaching three to four inches in diameter. Suffering from Type II Diabetes, she regularly used oral medications, did not want to use injected insulin, and did not test her blood sugar levels. She opened the blisters, hoping they would heal, but suffered bacterial infections.
Her physician cleaned the affected areas, applied a topical antibiotic, and wrapped the legs with gauze, applying tight elastic bandages over the gauze (Please see photo below). Unfortunately, the patient unwrapped her legs, which became reinfected. This happened several times, the last instance requiring hospitalization, before she consented to accept insulin therapy. With a few months of beginning the new therapy, her legs healed and blisters did not reappear. Within nine months, she lost a substantial amount of weight.
Do not try wrapping your own legs at home if you have large blisters, but do see your healthcare practitioner for help.
In the United States, Bullous disease of diabetes has been reported to occur in approximately 0.5% of diabetic patients. Male patients have twice the risk as female patients.— Maureen B Poh-Fitzpatrick, MD, et.al.Bullous Disease of Diabetes in Medscape; August 24, 2015
When in Doubt, Call a Healthcare Professional
Blisters anywhere on the body may or may not be caused by a chronic form of diabetes. Large blisters on the lower legs often prove to be just that. If your experience smaller blisters that are numerous or recurring, call a healthcare practitioner for help.
- American Diabetes Association. (March 31, 2017). Practice Resources for Diabetes Professionals. . Retrieved from www.diabetes.org › Research & Practice
- CDC: Diabetes. (May 14, 2015). Retrieved from www.cdc.gov/diabetes/home/
- Grand Rounds. (2014 - 2017). The Ohio State University, Wexner Medical Center and the Diabetes and Metabolism Research Center.
- Mutasim, Diya. (March 27, 2015). Blisters. Chapter Four. In Practical Skin Pathology; (pp 187 - 194).
- National Diabetes Education Program; NIH. (Summer 2016). The National Institute of Diabetes and Digestive and Kidney Diseases. Continuing Education.
- Poh-Fitzpatrick, Maureen B., MD, et.al. (August 24, 2015). Bullous Disease of Diabetes in Medscape. Retrieved from http://emedicine.medscape.com/article/1062235
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
Questions & Answers
I have something that started out as blister on the back of one heel, didn't pop, and turned into a black spot that's very sore. What should I do?
At this point, I advise you to call your health care provider as soon as you can. He or she may want to look at it and even have you take a picture with your phone and email it to them. You might also try a walk-in clinic in a grocery store - Like the Little Clinics in Kroger grocery stores. Another option is to call the local Nurses' Hotline at your nearest hospital, providing that they have such a hotline.Helpful 1
© 2010 Patty Inglish MS