Bullae - Causes, Treatment & Pictures


A bulla is a Latin word that means "bubble or spike." Any spherical protrusion, especially a cystic one can be referred to as bulla. A bulla is a fluid-filled sac or bullous lesion that forms when fluid becomes trapped behind a thin layer of skin. It's a blister of some sort. The plural form of bulla is bullae. The blister must be greater than 0.5 centimeters (5 millimeters) in diameter to be categorized as a bulla. Vesicles are smaller blisters ie less than 5mm in diameter.

Blisters that become infected can be quite painful. If left untreated, they can be dangerous. Starting in your blister, a bacterial, viral, or fungal infection might spread to other parts of your body. Blisters usually rupture and heal in one to two weeks on their own. It is always recommended to avoid trauma or friction to the bullae during this healing phase. 

Bullous skin disorders constitute an array of dermatoses, some of which can be fatal. Blisters and bullae in the skin and mucous membranes are the most common clinical characteristics, which result in skin and mucosal erosions when they rupture. When these bullae and erosions affect a large body surface area, the risk of dehydration, electrolyte imbalance, and infection increases along with it. 

Pathogenic autoantibodies can be found in both the blood circulation and the skin lesions in autoimmune bullous skin diseases, while hereditary variables play a larger role in the pathogenesis of non-immune bullous skin diseases.

Based on the skin layer that is affected and where the bulla forms, bullous skin disorders can be broadly divided into intraepidermal and subepidermal bullous skin diseases. Pemphigus Vulgaris and bullous pemphigoid are the two most frequent autoimmune bullous skin diseases. Below is the classification of bullous dermatoses as autoimmune bullous dermatoses and non-autoimmune bullous dermatoses:

Autoimmune bullous dermatoses   

  Non-autoimmune bullous dermatoses

Pemphigus Vulgaris

  Epidermolysis bullosa simplex

Bullous pemphigoid

  Hailey Hailey disease

Pemphigus foliaceus

  Darier's disease

Mucous membrane pemphigoid

  Epidermolysis bullosa dystrophica

Cicatricial pemphigoid

  Bullous drug eruptions

Dermatitis herpetiformis

  Friction blisters

Linear IgA bullous dermatosis

  Thermal burns

Epidermolysis bullosa acquisita

  Viral Infections

Pemphigoid gestationis

  Staphylococcal Scalded skin syndrome

Bullae- Causes

Autoimmune bullous dermatoses:

When our immune system fails to identify the structures that hold our layers of skin or mucous membranes together as self, autoimmune bullous skin diseases develop. The body's natural reaction is to create antibodies to combat the structures that it falsely recognizes as foreign.

Multiple hemorrhagic Bullae on back

Antibodies attack these structures, causing the skin layers to split and blisters to develop. These bullous diseases cannot be contracted from another person. 

There are a variety of other non-immune hereditary, medical and environmental causes of bullae. Let us have a look at the factors that can cause bullae:

  • Contact with irritants: You may acquire contact dermatitis if you come into contact with substances that irritate your skin, such as latex, cosmetics, or poison ivy. This is a type of irritant reaction that can result in bullae.

  • Friction: Friction is one of the easiest causes of bullae. This includes friction caused by rubbing against the inside of a shoe like a shoebite or using a shovel or other instruments repeatedly causing friction to the same area. Hands and feet are the most common sites for friction blisters.

  • Viruses: Bullae or vesicles can form on your skin if you are infected with certain viruses. Bullae is a symptom of many people who have shingles, which is caused by a virus. These usually emerge as a large group of fluid-filled blisters on specific regions of the body and are easy to burst. They're extremely painful as these viruses affect the nerves directly. Chickenpox, which is closely related to shingles, also causes smaller bullae. These occur all over the body and are itchy.

  • Medication: When we are allergic to certain drugs or components of the drugs, they can cause bullae on the skin as a part of the drug reaction. These bullae are usually itchy and reddish and occur minutes to days after intake of the offending drug.

Apart from the above-motioned causes, some other possible causes of bullae are:

  • Bacterial infections like impetigo

  • Frostbite

  • Sunburns, chemical burns, or thermal burns

  • Skin trauma

  • Hereditary conditions

Bullae- Symptoms

Tense Bullae on leg

Blisters can appear in a variety of dermatoses. Some of its causes are easily identifiable while others may require expert opinion and detailed investigations. The most common symptoms of bullae include the following:

  • The damaged skin will be elevated like a bubble and usually contains clear fluid. 

  • The blister or bullous lesion may rupture spontaneously, resulting in an open sore or erosion.

  • If your bullae are infected, the fluid within them may seem milky or pus-like. 

  • Some bullae may also contain blood. 

  • The skin around the blisters can be normal or reddish in appearance.

  • Blisters may be itching or painful.

What does a bullous disease look like?

Blisters and raw, itchy skin are common symptoms of bullous illnesses. The skin can itch and burn badly before blisters emerge. Blisters might persist for weeks or months depending on the type of bullous disease causing it. Blisters ultimately rupture and become erosions. They may then heal with hyper or hypo pigmentation or with milia. Blisters frequently reappear where the previous blisters healed.

Eating can be incredibly painful when bullous disorders affect the mucosa of the mouth. Acidic and spicy foods especially can cause a severe burning sensation in the mouth. When the lining of the nose is affected by bullous illness, nosebleeds can occur unexpectedly.

When should you see a dermatologist?

If you find bullae, see your dermatologist right away to get a proper diagnosis and treatment. Friction blisters usually heal on their own. However, if the area is uncomfortable or inhibits your movement, or if your bullae contain blood, you should consult a doctor.

If you have circulation problems or diabetes, it is extremely important to talk to your dermatologist about your bullae. These circumstances make it more likely that your bullae may become infected. Bullae can occur in response to a drug that you're allergic to or along with a fever. These situations necessitate immediate medical intervention. 

The condition causing the bullous skin lesions can be identified by dermatologists based on the location and size of the bullae, as well as changes in the bullae, your symptoms and other medical history. Your dermatologist may recommend a skin biopsy or further investigations to accurately diagnose the autoimmune and hereditary bullous conditions. Some blisters may be drained during your appointment with the dermatologist.



Bullae - Treatment

Treatment depends on the specific cause and condition behind the bullous lesions. Friction blisters can be drained if they are huge or causing discomfort, and preventive measures will be advised by the dermatologist. 

Bacterial and viral infections causing bullae will be treated with a course of the specific antibiotic and antiviral medication along with other measures.

Chemical and thermal burns will require antibiotics to prevent infection and dressings may need to be done on a daily basis.

Autoimmune bullous disorders need long term and holistic treatment. Many patients begin treatment with oral or topical corticosteroids. This medication can help the skin recover and also prevent new blisters by suppressing the immune system. The steroids should then be gradually tapered off when the condition stabilizes. Other immunomodulatory drugs like methotrexate, cyclophosphamide, azathioprine, or mycophenolate mofetil may be required in certain conditions to control the disease.

Steroids, dapsone, and other long term drugs have the potential to have major side effects. You'll need to be aware of the side effects of the medications you're taking so that you can notify your dermatologist if any issues arise. You'll also need to see your dermatologist on a frequent basis so that he or she can decide whether or not your treatment is working, as well as monitor and change your treatment plan accordingly. 

Blister draining

If your bulla or blister needs to be drained, it should be done by your dermatologist. You'll be less likely to become infected if it is done by an expert. Your dermatologist will sterilize the area first and then use a sterile needle or blade to puncture your blister. After draining completely, your doctor will apply a dry bandage to the area and may also start you on antibiotics. The skin over the drained bulla will be left intact and will help to heal the lesion and prevent infection.

Bullae - Prevention

Not all bullae, i.e. those induced by medical disorders, may be avoided. However, there are some simple precautions you may take to avoid them.

  • Bandages and protective covering: Place a bandage or protective covering over the inflamed or bulla-prone area to avoid the reformation of a bulla. 

  • Vaccinate against the diseases that cause bullae: Chickenpox and shingles can both be prevented with a single vaccine. 

  • Protect your feet: Wear clean dry socks and well-fitting, comfortable shoes. Blisters are more likely in shoes that are ill-fitting or rigid, such as high heels. Socks that regulate moisture or frequent sock changes might help prevent blisters on moist skin. Specially designed sports socks can help control foot perspiration during exercise and sports. It's also crucial to wear proper walking or hiking boots before embarking on a long hike.

  • Protect your hands: Wearing gloves when using equipment, doing physical labor, or playing a sport that requires gripping a bat will prevent the majority of blisters. Taping up the hands is a helpful practice in several sports, such as gymnastics, weightlifting, and rowing. Talcum powder also functions as a friction reducer and can be used in conjunction with gloves and tape, or on its own.

  • Protect yourself from sunburn: Bullae caused by sunburn can be prevented by using sunscreen and fully covered clothing.

Bullae usually heal within a week or two on their own. Preventing infection and promoting healing can be as simple as keeping the area clean, dry, and protected. More irritation or inadvertent disruption can be avoided by covering bullae with fresh bandages.

Consult a dermatologist if the bullae or blisters exhibit signs of infection, are painful, or are accompanied by a fever. Antibiotics or other therapies may be required. If the bullae spread or do not improve, you can schedule your appointment with our dermatologist at SkyMD who will give you medication to alleviate your symptoms. Simply download our app, fill out the needed information, and you'll be ready for your appointment through video call or chat, whatever option you want.


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