Bladder (Bulla, Skin Blister) – Causes, Treatment

Blase (Bulla, Hautblase)

Almost everyone knows skin blisters caused by minor burns or after wearing new shoes. If you know the causes of a skin blister, it can be easily treated and in many cases even avoided in advance.

What is a skin blister?

A skin blister, also called a bulla, is a skin condition where fluid collects due to skin irritation and the area of ​​skin visibly bulges outward.

This means that skin blisters belong to the so-called efflorescences in dermatology. If blisters are at least 5 mm in size, they are called skin blisters or bullae. Smaller accumulations of fluid are called vesicles or vesicles in dermatology .

In medicine, there are three types of skin blisters. Subcorneal blisters are those that lie under the horny layer, intraepidermal blisters are in the so-called epidermis, and blisters lying under the dermis are called subdermal.


Blisters form as a result of excessive skin irritation. A particularly typical cause of a skin blister is friction, for example from footwear that does not fit properly or is too damp.

The friction creates heat that burns the skin. However, skin blisters also develop after any other type of second-degree burn . This does not only apply to physical heat sources such as the sun, fire or the like.

Skin blisters can also be caused by chemicals. In addition to burns, bullae can also result from second-degree frostbite or infection. Usually, a blister does not appear immediately, but develops over a period of time, sometimes only after a few hours.

Diseases with this symptom

Diagnosis & History

Although a skin blister is painful as long as it affects comparatively small areas of skin, it is generally harmless in terms of health. Treatment by a doctor is therefore usually not necessary.

Since the occurrence of a blister is announced in advance by pain, the cause of the skin irritation can be eliminated in many cases and the blister can be prevented. If a blister can no longer be prevented, the top layers of skin peel off and protein-poor tissue fluid accumulates.

If measures such as cooling or ointments are taken directly for blisters, their formation and later size can be influenced. Once a bubble has formed, it takes time to disappear. The skin usually recovers after a few days. Blisters that have burst open usually take a little longer to heal. Nevertheless, skin blisters usually disappear completely and leave no scars .


A skin blister is usually harmless and will burst on its own. However, if you don’t wait and open it yourself at home, you run the risk of infection. This complication occurs when sterile cutlery is not used – this is not easy to do at home. Boiling the tool in salt water or exposing it to a sufficiently high heat source can kill germs, but if this is not done thoroughly, opening the bulla will put the germs in the very spot where they have the greatest ability to cause infection.

The opened bladder becomes infected and since the affected area is already weakened anyway, such infections usually do not go away on their own after a short time. Complications can also occur if the skin blister is in an awkward position that normally needs to be strained. Blisters on the feet are particularly common, they occur exactly at the stress points.

If the skin blister is not opened, the affected person may no longer be able to step properly and risk tension and incorrect strain on the muscles that he uses for alternative movement. Since these muscles are not made for this, they react with pain and subsequent overload. In order to avoid this type of complication, it is often considered better to have the bladder opened by a doctor.

When should you go to the doctor?

People who notice skin changes with blisters should always consult a doctor (e.g. dermatologist ). It could be a bacterial or viral skin infection, an autoimmune disease, or a food allergy. Immune-depleting skin diseases associated with blistering are called bullous dermatoses and are very rare.

In bullous dermatoses, the organism forms antibodies against cell components of its own skin. This loosens the top layer of skin and small or large blisters form. The antibodies have a massive impact on the skin’s stability, destroying not only the epidermis but also the deeper layers of the skin. There are several diseases that belong to the group of blistering dermatoses. They all look alike. If a blister can be displaced laterally within healthy tissue, this indicates a specific autoimmune disease.

The doctor tests for antibodies (immunofluorescence), which can be detected in the skin cells and in the blood. If the blisters are due to a bacterial infection, treatment with antibiotics is advisable. Sun or cold can damage the skin so badly that fluid-filled blisters form. A common blistering skin condition caused by a virus is herpes simplex type 1. It occurs primarily on the lips and can be very painful. Herpes simplex type 2 appears in the genital area and is also caused by viruses.

Treatment & Therapy

Many people tend to pop a blister. However, it is better to leave the bladder as it is. The skin of the blister, which stretches over the wound, protects it from the ingress of bacteria .

With the ongoing healing process, the blister also forms back. The healing process can be accelerated with various ointments from the pharmacy. If you decide to pierce a blister, you should choose a pointed and, above all, sterile object. Lancing a blister may be necessary if the blister is, for example, under the sole of the foot or in other parts of the body where a blister cannot heal on its own.

After the wound water has drained from the punctured blister, a blister plaster is stuck over the wound, which takes over the function of the blister skin and protects the wound from possible infections. In some cases, the skin blisters can also burst on their own. This, too, is not untypical and usually does not require treatment by a trained medical professional.

However, it can become problematic if the wound becomes infected. If bubbles burst, they reveal the dermis. Compared to the epidermis, the dermis is much lighter and redder and releases wound fluid. This is the ideal breeding ground for bacteria of all kinds, which have easy access through the unprotected and open wound. If the wound becomes infected, a doctor must be consulted to provide medical care for the wound.

Outlook & Forecast

The outlook for a blister’s progression varies depending on the cause. Blisters caused by mechanical stress usually regress on their own over time and heal without scarring. Nevertheless, inflammation can also develop, especially if the outer skin of the bladder is damaged. If the blisters are detected early, they can usually be treated well with medicinal ointments.

Scars can usually only remain if blisters form as a result of intense exposure to radiation, burns or frostbite. If allergies are the trigger, the course depends on the strength of the allergic reaction. Since allergies usually last a lifetime, the only way to prevent blisters from reoccurring in this case is to avoid future contact with the allergenic substance.

Even when autoimmune diseases cause blisters, the prognosis varies greatly depending on the extent of the immune response . Treatment is essential as these diseases can be fatal if left untreated. Drugs are usually used as therapy that curb the immune activity that causes symptoms such as blistering. These immunosuppressive drugs usually have to be taken for life, since the underlying autoimmune disease is usually not completely curable.


Before a blister develops, the affected area already hurts. For blisters caused by mechanical friction, skin blisters can be avoided if the condition causing the friction is eliminated directly.

Blisters from burns can also be prevented or at least reduced in size by applying extensive heat directly to the affected area. Blister plasters are not only suitable for treating blisters, but also for prevention. However, blistering can also be completely prevented by avoiding the causes of skin blisters.

In many cases it is enough to change a few everyday things. Only suitable footwear with synthetic and well-fitting socks should always be worn. Socks should also be changed regularly to avoid moisture in the shoe. If you can foresee that hiking or running will increase the stress on your feet, you should slowly get used to this stress to prevent skin blisters.

To reduce moisture through sweating, there are also so-called antiperspirants in the pharmacy, which can be applied to areas of the skin and thus reduce the release of sweat. Anyone who handles fire or hot objects should wear protective clothing and be particularly careful near heat sources. In the household, oven gloves or the like are often sufficient to avoid minor burns.

You can do that yourself

Everyday and self-help is usually very possible when skin blisters appear. If the skin blister forms on the foot due to new shoes, preventive measures can be taken in advance. For example, the formation of a blister on the foot is announced by pain in the affected area and reddening of the skin. A preventive measure is to put a plaster with soft padding on the reddened area or to put a little padding in the shoe itself. Special blister plasters are better than a normal plaster . They are specially designed for pressure relief, pain relief and sterile coverage.

If skin blisters are expected to form following a scald from hot or boiling water, cooling the scalded skin will help limit the inflammatory response initiated by the immune system. Existing skin blisters that can no longer be prevented in advance should, if possible, be given the opportunity to heal on their own without opening them. If the blister is very annoying, it can also be carefully opened with a pointed object, such as a sewing needle. It is advisable to sterilize the tip of the needle beforehand with alcohol or by heating it up in the flame of a lighter, because the tissue fluid in the bladder is an ideal breeding ground for many pathogenic germs.

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.