The skin is the body’s largest organ, and it functions as part of the integumentary system, which works to protect the body from different kinds of damage. Your skin shields you from environmental elements, ultraviolet radiation, chemicals, weather conditions, and microbes. The skin also contains nerves that allow us to access sensations like touch, heat, and cold.
Generally, there are three main layers of skin that offer all of these protections. These layers include:
- The epidermis – The epidermis is the water-resistant outer layer of skin and the body’s first line of defense against environmental elements, ultraviolet radiation, bacteria, and other germs.
- The Dermis – The dermis is the layer of skin under the epidermis. This layer of skin contains connective tissues and houses your body’s hair follicles, sweat and oil glands, and blood vessels.
- The hypodermis – The hypodermis is made of subcutaneous (under the skin) fats, connective tissues, blood vessels, and nerve cells – it is the layer of skin where fat is deposited and stored. The blood vessels in the hypodermis are also bigger and connect to the rest of your body.
A blister is a pocket of fluid between the upper layers of skin. The blister bubble is formed from the epidermis, the uppermost layer of skin. Its purpose is to protect and cushion the layers below. Blisters can be filled with serum, plasma, blood, or pus depending on how and where they are formed.
Overall, blisters fall into three main types:
- Friction blister – A friction blister (also known as a water blister) is a collection of clear, colourless fluid trapped between or beneath the top layer of skin, which is the epidermis. Water blisters typically form when skin rubs against a surface, causing friction. Burns, frostbite, or infections can also cause water blisters.
- Heat blister – A heat blister (burn blister) forms over skin that has suffered a mild to severe burn from heat or chemical exposure. It’s important to protect a burn blister while the skin underneath heals. Bursting a burn blister can lead to infection.
- Blood blister – A blood blister is a specific type of blister due to damage to blood vessels and tissues just under the skin, which causes blood and other fluids to pool and form a bump. Blood blisters usually form after a strong pinch of the tissues, but there are other causes as well.
Causes & Symptoms
The most common type of blister for most people is the friction blister. In their most basic form, they occur due to increased shear stress between the surface of the skin and the rest of the body. The layer of the skin most susceptible to shear forces is the stratum spinosum. As this layer tears away from the tissues below, a plasma-like fluid leaks from the cells and begins to fill the gap that is created.
This fluid encourages new growth and regeneration. Roughly 6 hours after the blister appears, cells at the base of the blister begin to take up amino acids and nucleosides. These are the building blocks of protein and DNA. At approximately 24 hours after the blister has formed, cell division is markedly increased. New skin layers above the stratum spinosum are steadily formed. After 48 hours, a new layer of skin can be seen, and finally, at 120 hours, a new upper layer of skin is visible. As these new cells develop, the fluid is rea sorted and the swelling subsides.
There are other various causes of blisters, including the following:
- Temperature extremity – The timing of blister formation helps categorize burns. Second-degree burns will blister immediately, but first-degree burns blister a couple of days after the incident. In addition, frostbite also produces blisters.
- Chemical exposure – Skin can occasionally blister because of certain chemicals. It can affect some patients in contact with cosmetics, detergents, solvents, nickel sulfate, insect bites, and stings.
- Crushing / Pinching – If a small blood vessel near the surface of the skin is ruptured, blood can leak into the gap between the layers of skin, causing a blood blister to form. This is a blister that is primarily filled with blood.
Additional symptoms linked to blisters include:
Blisters can be caused by physical factors that irritate the skin, such as friction (rubbing the skin), irritating chemicals, or extreme cold or heat. Blisters on the feet can result from shoes that are either too tight or rub the skin in one particular area. Blisters also can be caused by contact dermatitis, a skin reaction to some type of chemical irritant. Intense cold can trigger frostbite, which often leads to blisters once the skin is rewarded. Any type of burn, even sunburn, also can cause blisters.
Infections that cause blisters include bullous impetigo, an infection of the skin caused by staph bacteria; viral infections of the lips and genital area due to the herpes virus; and chickenpox and shingles, which are caused by the varicella-zoster virus.
Allergic contact dermatitis, a form of dermatitis or eczema, may result in blisters. Allergic contact dermatitis is caused by an allergy to a chemical or poison, such as poison ivy, poison oak, or poison sumac.
Many medications, such as nalidixic acid and furosemide, can cause mild, blistering skin reactions. Others, such as doxycycline, can increase the risk of blistering sunburn by increasing the skin’s sensitivity to sunlight. In more dramatic cases, medications can trigger more severe, even life-threatening, blistering disorders, such as erythema multi force or Toxic Epidermal Necrolysis (also known as TEN), an illness that causes severe skin damage and typically involves 30% or more of the body’s surface.
Numerous skin diseases cause blisters. Examples include dermatitis herpetiformis and pemphigus. There also are inherited forms of blistering skin conditions, such as epidermolysis bullosa (in which pressure or trauma commonly leads to blisters) and porphyria cutaneous tarda.
Who gets Blisters?
Certain risk factors associated with blisters may include the following:
- Allergies – Patients who are living with eczema or allergy reactions to certain things (such as foods, animals, pollens) may be at risk of developing blisters anywhere on the skin.
- Sports – Athletes who need sport implements to compete are prone to blisters because of the friction caused by the sport implement and the hand. These sports include baseball, softball, weightlifting, rowing, and discus. Gymnasts are especially susceptible to blisters in the hand caused by friction between the gymnast’s hands and the bars when they rotate.
- Skin diseases – Patients who are experiencing skin diseases, such as pemphigoid and pemphigus, are prone to experiencing blisters as well.
How Do They Affect You? How Serious Are They?
If severe blisters are left untreated, serious infections can begin to spread to other areas of your body. In addition, bacteria can enter the blistered skin and result in a condition called cellulitis. This is a rapidly spreading skin infection. It can quickly become a medical emergency if it spreads to your lymph nodes or bloodstream. Infected blisters can also lead to sepsis in severe cases.
This happens when certain chemicals released by your immune system trigger a chain reaction in your body. Eventually, this can lead to septic shock. Septic shock is fatal about half the time. However, most people recover from milder cases of sepsis.
Recommended Treatment & Rehabilitation
During the diagnosis of a blister, healthcare providers can often diagnose blisters by simply looking at your skin. If your provider thinks you may have an infection or a skin disorder, a blister biopsy may be done. A piece of the blister is removed and checked under a microscope.
Once your doctor has a better idea of what is causing the infection, they might prescribe oral antibiotics or topical antifungal medications. They might also perform a quick in-office procedure to drain the blister. It is very important that you leave this process to your doctor. Doing it on your own can worsen the infection or cause it to spread to nearby areas.
Blisters generally heal on their own within a few days. You can do a few things at home to make them more comfortable, such as the following:
- Clean the wound – Run the area under warm water and gently massage it with soap. Continue rinsing and washing for 3-5 minutes. Repeat this method twice a day.
- Soak the wound – Soak your wound in a homemade saline solution. You can make this by adding 1 teaspoon of salt to 1 cup of warm water.
- Treat the wound – After washing both your hands and the wound, apply a topical antibiotic ointment.
- Anti-inflammatory medications – Take non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, to help reduce pain and swelling.
- Ice application – Apply a cold or ice pack which may help reduce swelling and discomfort.
You have several options for preventing blisters. Most involve preparation and caution. Preventing blisters depends on the type of blister:
- Blood blisters – Stay alert when using tools or things that can pinch. Wear gloves when working with pruners, strong pliers, or in other tight situations.
- Friction blisters – Make sure your shoes fit well and do not rub. Break-in new shoes before wearing them for extended periods. Wear gloves to protect your hands if you plan on doing a lot of manual labor. Wear properly fitting clothes to prevent chafing that can lead to blisters on other parts of your body.
- Heat blisters – Use sunscreen if you plan to be in the sun for an extended period. It is recommended to be careful when handling hot items or working around a fire. In addition, wear weather-appropriate clothing to avoid frostbite. If your skin gets frostbitten, slowly raise your body temperature using lukewarm water.
Alternative & Homeopathic Treatment
Certain natural remedies for blisters on the feet, toes, and heels include:
Aloe Vera leaves contain a gel-like substance that is well known for its healing properties. Studies have shown that the compounds inside aloe vera gel reduce inflammation, increase collagen production, and stimulate cellular regeneration, which can promote more efficient wound healing. You can purchase ointments and skin products that contain aloe vera over the counter.
Vaseline can promote healing of the affected area.
Coconut oil contains lauric acid, a type of fatty acid that can hydrate the skin and reduce inflammation. Coconut oil may also promote tissue repair and increase wound healing. People can dip a cotton ball into melted coconut oil and gently tap the oil onto the blister.
Calendula comes from marigold plants. It contains several antioxidants that may help reduce inflammation and increase skin healing. Although calendula appears safe for external use, it can cause contact dermatitis. Patients using calendula for the first time should test a small amount before using it to treat blisters or other sensitive areas of the skin.