Definition
Blisters are skin lesions that can occur under unaccustomed pressure or friction. The feet in particular are predestined for the occurrence of blisters, the causes can be different. Blisters on the foot are mostly the result of mechanical friction, but there are also rather rare causes for blisters on the foot. Blisters on the foot can also vary in size and composition.
Causes
Blisters on the foot usually occur as a result of mechanical stress. This includes unusually long periods of stress, such as long walks, but also the first-time wearing of new shoes. Especially the footwear is crucial for the occurrence of blisters.
As a rule, every new shoe can lead to blisters, but especially sandals, shoes with heels or generally shoes with point loads. Moisture can increase the risk of blisters on the foot. Dry, well-padded, already broken-in shoes in combination with friction-free socks usually do not cause problems under normal load. In contrast to the hands, the feet are usually protected against chemical stress by the footwear, but walking barefoot can be a risk factor for contact with chemicals or for infections. A blister on the foot must be distinguished from warts, which can also occur very frequently on the foot.
Diagnosis
The diagnosis of a blister on the foot is usually a gaze diagnosis; it can also initially manifest itself through pain on the affected foot. Blisters of mechanical causes usually occur at the stressed areas, as this is a reaction of the skin to “cushion” the excessively stressed area. The anamnesis also leads to the diagnosis of blisters on the foot. Affected persons usually describe long walks, other intensive sporting activities, wearing new shoes or similar.
Symptoms
A blister on the foot can be accompanied by pain, which even makes running and walking a torture. Before the blister formation, the affected area is often reddened and painful, later on a fluid-filled skin rash forms. Blisters on the foot occur preferably on the heel, on the sole or in the area of the toes.
The blisters can be filled with clear liquid, rarely also blood admixtures and pus. Once the bladder is opened, pathogens can enter and lead to inflammation. There is severe pain and the bladder can fill with pus.
How long the bladder will remain open depends on the extent to which the area is additionally irritated. The piercing of a bladder should be avoided if possible, usually it leads to a prolongation of the healing process. After healing, a thicker cornea forms at the affected area to protect it from further friction.
Even before the blister itself appears, the affected person feels unpleasant friction. The skin skins many sensitive nerve endings, injuries can cause severe pain. Blisters on the foot can be very painful, especially because immobilisation and covering to protect the affected area is usually difficult.
Local ointments can be used for relief, blister plasters help to cushion the foot. Especially if a blister is opened by improper manipulation, pathogens can enter and infect the wound. The skin layers under the top layer are very sensitive to pain.
Puncturing blisters should generally be avoided and should only be carried out by an experienced doctor if there is no way around it. If a blister has become infected and the pain is very severe, a doctor should always be consulted. A blister is caused by rubbing of the skin, resulting in minor injuries to the skin and a local reaction.
This consists on the one hand in the formation of a blister as padding of the affected area. On the other hand, a variety of defensive reactions can be activated, especially when pathogens enter the wound. The substance histamine in particular, which is released by the body during inflammatory reactions, can lead to unpleasant itching.
It is important not to touch or scratch the affected area, as further pathogens can penetrate and the skin injury can become infected. You can read about what you can do against itching in our article Itchy skin – what to do? Pus develops during inflammatory reactions and consists of melted tissue and defence cells.
Inflammation of a blister on the foot is usually caused by opening the affected area. Blisters should therefore not be punctured! If the wound becomes inflamed, the yellowish pus appears and there is severe redness and pain in the injured skin area.
Open blisters should be thoroughly disinfected and covered; the uppermost layer of skin should never be removed. Larger blisters should only be punctured by a doctor using a sterile needle to allow the fluid to drain away. Purulent infections should be examined by a doctor.
It may also be necessary to empty the bladder. In rare cases it may also be necessary to prescribe an antibiotic. In most cases, however, just the proper emptying of the purulent bladder and the application of an ointment will help to improve.
A visit to the doctor is unavoidable if fever, chills, vomiting, diarrhoea or discolouration of the affected limb occurs. Although very rare, pathogens can enter the bloodstream and cause a serious systemic inflammatory reaction, known as blood poisoning. Blood poisoning, also known as sepsis, is a systemic reaction of the body to an infection with pathogens, usually bacteria.
Sepsis can also occur in the infection of skin wounds when pathogens enter the bloodstream and cause an immune response. In theory, therefore, an infected bladder on the foot can also lead to blood poisoning. However, such injuries usually heal without serious consequences.
Nevertheless, a doctor should be consulted if the bladder is severely infected. Signs of blood poisoning are fever, chills, nausea, vomiting or discoloration of the affected area. A doctor must be consulted at the latest for these symptoms. Blood poisoning is a serious reaction that can be fatal. How to recognize blood poisoning, you will learn in our article Symptoms of blood poisoning!
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