Blisters are a common skin lesions that most of us experience at some point in life. These lesions can also form within the cavities, such as the mouth. While it is usually not a serious skin problem, it can be unsightly and painful. Over time the cause of these blisters can also contribute to the formation of calluses, which may persist for longer periods of time than blisters.
What are blisters?
Blisters are tiny fluid-filled lesions that form in the superficial (outermost) layers of the skin. It is the body’s way of protecting the deeper tissue from injury. Blisters mainly arise where there is repeated and forceful abrasion/friction of the skin. It is therefore more common on the hands and feet after strenuous physical activity involving the surfaces of the palm or soles. However, it can also occur for reasons like with infections, autoimmune diseases and allergies.
Most blisters are filled with a clear fluid and are therefore referred to as “water blisters”. However, some may be filled with blood, hence the term “blood blisters”. It can also be filled with pus and this is more correctly known as an abscess or boil. Blisters should never be burst as the break in the skin can increase the risk of infections. Some blisters will resolve while others will burst on its own. Most blisters disappear within a week after it forms.
Why do blisters form?
Blisters occur when the skin is damaged and fluid fills just underneath the outermost layers. This cushions the deeper tissues and protects it from damage. If the trauma is ongoing over a period of time and not very forceful then the skin will become thick. This is known as a callus. However, when the trauma is sudden, repetitive and forceful then a blister will form. Apart from mechanical trauma like friction, it can also form with burns.
The area become red due to the injury and around it is a paler color. Usually there is a burning sensation, pain and tenderness. This is a result of inflammation and is the body’s way of signaling that the area is undergoing injury and damage, and any further trauma should be avoided. The fluid that fills up to form a blister is tissue fluid. It is the same type of fluid that circulates in the bloodstream and exits and enters blood vessels.
Causes of Blisters
There are many different causes of skin blisters which arises for a variety of reasons. Some of these factors are the more common causes of blisters as is the case with trauma and friction or chaffing in particular. Other conditions are less common or even rare but need to be considered when the obvious causes of blisters has been excluded. Always consult with a medical professional in the event of persistent or recurrent blisters.
Trauma is the main cause of blisters. Usually this is with mechanical injury like friction and blisters are therefore often referred to as friction blisters. For example, poorly fitting shoes can results in friction between the inner surface of the shoe and the feet which may then result in a blister.
Other types of trauma where blisters may form includes burns, insect bites/stings, electromagnetic trauma like sunburn and chemical injuries like contact with caustic substances. Exposure to radiation as well as frostbite can also result in skin blisters on the exposed area.
Blisters may form with various different types of infections. This includes bacterial infections of the skin (impetigo) or follicles (folliculitis) which may arise with many species of bacteria that gain entry into the skin. Staphylococci and streptococci bacteria are the more common causes of bacterial skin infections and some of these bacteria naturally reside on the skin.
Certain viral infections may also cause skin blisters. It is seen with viral infections such as chickenpox, shingles, herpes simplex virus (HSV) and syphilis. Blisters may also form with fungal infections of the skin. This includes dermatophyte infections (ringwom) and yeast skin infections (cutaneous candidiasis). Scabies is an infestation with tiny mites that burrow into the skin and blisters may form in the affected area.
Other Skin Diseases
Blisters may occur in a number of different skin conditions, either as a feature of the disease itself or with complications like a secondary bacterial infection of the diseased skin. This may be seen with:
- Dermatitis, including atopic and contact dermatitis.
- Skin diseases where blisters are one of the main symptoms such as dyshidrotic eczema (pompholyx), bullous pemphigoid, pemphigus vulgaris, dermatitis herpetiformis, epidermolysis bullosa, chronic bullous dermatosis of childhood and bullous ichthyosiform erythroderma.
- Skin allergies such as erythema multiforme.
- Skin rashes due to drug hypersensitivity.
Treatment of Blisters
Contrary to popular belief, blisters should not be burst by squeezing or pricking with a needle. This break in the skin can result in infections at the site and worsen the condition. Rather a blister should be drained by a doctor if it is deemed necessary. An antimicrobial ointment needs to be applied on the area afterwards. This sterile drainage is best done by a medical professional but can be done at home with the appropriate measures taken if required.
Blisters will often heal on its own within 5 to 7 days. If the trauma or any other underlying cause is continuous then it may not heal easily or there could be a recurrence. Antibiotics or antimicrobial ointments may be administered even if there is no infection in order to prevent a secondary infection at a later stage. Always keep the area clean by washing with an antibacterial soap on a regular basis throughout the day.
Prevention of Blisters
In most cases blisters can be prevented as it is often due to trauma. Minimizing this trauma or appropriately protecting the skin where the trauma occurs will reduce the likelihood of a blister forming. Simple measures like using thick socks or wearing loose-fitting shoes can easily prevent blisters on the feet when tight-fitting shoes is the cause. Similarly gloves can be used to prevent blisters on the hands. For blisters caused by sunburn, preventative measures like using sunscreen will suffice.