What are Diabetic Bullae?

They are fluid, or blood filled sacs or lesions, that appear when fluid is trapped under a thin layer of your skin. Bullae are similar to blisters and vesicles, with the only difference being in size.

Vesicles are about the size of the top of a pin, reaching a maximum size of about 10 millimeters in diameter. After this point, a vesicle is considered a blister. When a blister becomes larger than 1 centimeter in diameter, it is a bulla. (Bulla is the singular form of bullae.)

Diabetic bullae are rare, but appear more often in those who have had diabetes for a longer period of time, or who have experienced complications due to diabetes.

A clear bulla, which can be self healingThere are two types of Diabetic bullae: 1) Intraepidermal bullae, characterised by blisters that are filled with a clear,Infected Diabetic Bulla
sterile viscous fluid. These blisters generally heal on their own in two to five weeks without scarring. 2) Subepidermal bullae, characterised by blisters filled with blood. Scarring and atrophy may occur after healing.


What Causes Bullae?

Bullae and blisters are common occurrences that can be caused by various medical and environmental factors. The exact cause of the blisters is yet to be confirmed, multiple factors are most likely in play. From neuropathy (nerve), nephropathy (kidney), change in skin and blood vessel structure, to sun exposure, and/or side effects of medications, are all possible factors.   Age does not seem to be a factor, as the blisters have been reported as early as the teen years, all the way through the age spectrum to the 80’s. The blisters are more common in men than women. Some possible factors include:


It’s one of the most common causes, and occurs from using a shovel or other tool, or rubbing against a shoe. Friction blisters appear most often on your hands and feet.

Contact Dermatitis

If you come into contact with things that irritate your skin, like latex, cosmetics, or poison ivy, you could develop a condition called contact dermatitis. Contact dermatitis is an allergic reaction that also causes bullae.

Other Causes

Other potential causes of bullae and blisters include:

  • – disorders of the skin, like impetigo
  • – chickenpox
  • – thermal burns, or sunburns
  • – trauma to your skin

Recognising When You Have a Bulla

You should be able to tell that you have a bulla or blister simply by looking at it. The skin that is affected will be slightly raised and have a liquid that resembles water or blood inside. It is not recommended that you pop the bulla or remove the skin covering your bulla, though it may be tempting to do so.

That skin acts as a protective barrier against infection. If you break the skin in order to drain your bulla, you risk allowing bacteria into the wound.

If you have an infected bulla, the normally clear liquid inside it may appear milky. If your bullae are a result of trauma, they may contain blood as well.


You should see your doctor if your bulla is causing you pain, or restricts your movement at all. If you have problems with your circulation or if you have diabetes, talk to your doctor before trying to treat your bulla at home.

Home TreatmentGauze pads help to protect the bullae

Blisters and bullae can usually heal naturally if they are left alone. To avoid further irritation, or making your bulla worse, you can put a protective bandage over the area. A gauze pad is best, since the fabric absorbs moisture, while still allowing your bulla to breathe.

Try not to put pressure on the area, because this could cause your bulla to burst. However, if your bulla contains blood, it should be tightly wrapped. This will stop the bleeding. You might try over-the-counter antiseptic ointments from the pharmacy to use on your blister.

Medical Treatment

If your bulla or blister needs to be drained, you should have a doctor perform the procedure. This will lower your risk of infection. During your visit, your doctor will likely swab the area with alcohol to remove any dirt or bacteria. Then he or she will puncture your blister, using a sterile needle.

After the blister has drained completely, he or she will apply a bandage with antiseptic ointment onto the area. After a few days, you may choose to remove the skin that was covering your bullae. You can sterilize scissors with alcohol and use them to remove the extra skin.

Preventing Bullae and Blisters

Diabetic Socks will help protect the feetNot all bullae and blisters can be prevented. However, some simple steps can help to keep you bulla free. To prevent developing a bulla as a result of friction, try placing a bandage or protective covering over the irritated area, before beginning the activity.

If you play sports, there are socks available with additional padding for areas of the foot prone to blistering. You can also add fabric like moleskin to your shoes if they rub on your skin, and purchase blister plasters and wear in advance.

                                                            Your feet mirror your general health . . . cherish them!

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