A bulla is described as a sac or lesion filled with fluid that is trapped beneath a thin layer of skin. It is a form of blister that is bigger than 0.5 centimeters in diameter.
What are the causes?
- Friction – this is the usual cause, usually from using a shovel or any tool or rubbing against the interior of a shoe. The blisters are likely to form on the feet and hands.
- Contact dermatitis – exposure to irritants such as cosmetics, latex or poison ivy can trigger a skin reaction which includes bullae.
- Viruses – certain viral infections can trigger the formation of bullae on the skin such as shingles or chickenpox
Other possible causes include frostbite, reactions to certain drugs, skin trauma, burns and skin conditions such as impetigo.
What are the signs?
It is easy to pinpoint a bulla. The affected skin is usually slightly elevated and contains clear fluid inside.
In case it is infected, the fluid within might appear milky. If the bulla is brought about by any form of trauma, it might include blood as well.
Caring for a bulla
There are various treatment options for a bulla which is based on the root cause and if drainage is necessary.
A bulla due to friction naturally heals if left alone. A protective bandage can be applied over the site to avoid further irritation or aggravating the bulla. A gauze pad is the ideal option since it absorbs moisture while allow the bulla to breathe.
Do not attempt to pop one on your own. If the skin is opened to drain the bulla, there is a risk for infection.
In case a bulla requires drainage, the doctor will carry out the procedure to reduce the risk for potential infection.
The doctor will swab the site with a cleanser to eliminate any dirt or bacteria. The blister is punctured using a sterile tool. Once the blister is entirely drained, a dry bandage is applied. After a few days, the dried skin covering the bulla can be removed with scissors cleaned with iodine.