9 Causes of Blisters on Feet

Most people will have experienced a foot blister—a small pocket of fluid beneath the skin of the foot—at some point in their life.

Friction, or forceful rubbing, is the most common cause of blisters on the feet. This can be due to poor-fitting or loosely tied shoes rubbing against your skin. Damp feet—from sweat or other moisture—are also more likely to blister. You can typically feel a friction blister forming.

Sometimes, blisters form on the feet for less obvious reasons. Unexplained blisters on the feet can be caused by athlete’s foot, contact dermatitis, eczema, or psoriasis. Other reasons for unexplained blisters on the feet include poor circulation, insect bites, and a rare genetic condition known as epidermolysis bullosa simplex.

This article discusses the different causes of foot blisters. It also explains the accompanying systems of foot blisters, how to treat foot blisters, and when to see a healthcare provider.

Excessive Foot Moisture

Excessive moisture can clog the pores on your feet which, in turn, can lead to the formation of blisters between the toes and anywhere moisture builds up. Blisters of these sorts are common in runners due to the accumulation of sweat in their shoes and socks.

How to Treat Excess Foot Moisture

There are several things you can do to prevent the build-up of foot moisture:

• Wear moisture-wicking socks.
• Wear breathable shoes like sandals.
• Change your socks or shoes when your feet become moist or sweaty.
• Avoid shoes that trap moisture, such as leather boots, if you intend to wear them for a long time.
• Use foot antiperspirant to reduce sweating.

When blisters form due to excess moisture, they can become more susceptible to infection. Keeping your feet dry can help prevent this.

Sunburns

A sunburn is caused by overexposure to the sun’s ultraviolet (UV) rays. It can occur on almost any part of the body, including the tops of your feet.

Sunburn blisters can be extremely painful and may develop quickly based on your skin type, season, geographic location, and time of day you are in the sun. People often get these blisters when they fall asleep in the sun.

How to Treat Sunburn Blisters

Sunburn blisters usually heal on their own, but you can help speed your recovery in several ways:

• Do not pop blisters as this can lead to infection.
• Use a cold compress or take a cool shower to ease the pain.
• Take an over-the-counter pain reliever like Tylenol (acetaminophen).
• Apply aloe gel to cool the feet and relieve pain.
• Avoid further sun exposure by wearing socks when outdoors.
• Drink plenty of water since blisters can cause your body to lose moisture and lead to dehydration.

Allergic Contact Dermatitis

Allergic contact dermatitis is a type of rash that occurs when you come into contact with an allergy-causing substance, known as an allergen. The rash can develop within minutes to hours of exposure and last up to four weeks in some cases. Tiny blisters are common.

You can get allergic contact dermatitis by walking barefoot through poison ivy. If you have a latex allergy, shoes made with latex rubber can trigger a reaction. Similarly, socks made with copper-infused fibers can also cause a rash with blisters if you have a metal allergy.

How to Treat Allergic Contact Dermatitis

The best way to prevent allergic contact dermatitis is to avoid known allergens. If contact does occur, you can usually treat the rash with topical corticosteroids (steroids) to reduce inflammation and itching. Severe cases may need oral steroids like prednisone.

Psoriasis

Psoriasis is an autoimmune disease that causes itchy and scaly red patches on the skin. Although the patches are most common on the knees, elbows, torso, and scalp, they can also develop on the hands and feet.

Psoriasis occurs because the immune system is overactive and speeds up skin cell growth. This causes cells to accumulate faster than they can be shed, causing thick, flaky areas of skin called plaques. Tiny blisters can form as fluids beneath the skin start to pool.

A rare form of psoriasis, known as pustular psoriasis, can cause white or yellow blisters filled with pus. When it affects the feet, it is called palmoplantar pustular psoriasis.

How to Treat Foot Psoriasis

Foot psoriasis may be treated with the following medications and therapies:

• Occlusive steroid therapy involves covering the foot with plastic after applying steroid cream.
  
• Oral retinoids are drugs taken by mouth that slow skin cell growth
  
• Topical calcineurin inhibitors are drugs that suppress the immune response.
• Phototherapy uses a special band of UV light to slow skin cell growth.

Psoriasis Doctor Discussion Guide

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Dyshidrotic Eczema

Although dyshidrotic eczema typically affects the hands, it can also cause blisters on the soles of the feet. The outbreak of blisters, which resembles tapioca pudding, can flare up suddenly and resolve just as quickly. Young adults are most commonly affected.

Dyshidrotic eczema is often triggered by contact with concrete, nickel, or cobalt as well as personal care products like shampoo or soap. Stress, sweat, and heat are other potential triggers. The cause of dyshidrotic eczema is unknown but does not involve an allergic reaction.

How to Treat Dyshidrotic Eczema

The treatment of dyshidrotic eczema is focused on caring for the blisters. This may involve medicated soaks and cool compresses to dry out the blisters and ease discomfort. Moisturizers and lotions can reduce skin dryness as well as the risk of flare-ups.

Mild cases may be treated with topical corticosteroids. If your condition is severe, oral steroids or a steroid shot may be preferred.  

Vesiculobullous Tinea Pedis

Vesiculobullous tinea pedis is a type of athlete’s foot that affects the inner surfaces of your feet. It is caused by an overgrowth of fungus that thrives in damp, warm environments like sweaty socks. It is called vesiculobullous because it involves vesicles (tiny fluid-filled sacs) and bullae (large blisters).

People who wear closed-toe shoes in hot, humid environments are more susceptible to this type of athlete’s foot. Other risk factors include obesity, a weakened immune system, and residing in a long-term care facility.

How to Treat Vesiculobullous Tinea Pedis

Vesiculobullous tinea pedis, like any other form of athlete’s foot, is treated with topical antifungal medications. They are applied to the skin once or twice daily to help clear the fungus. The treatment lasts between two and four weeks, but recurrence is common.

Insect Bites

Insect bites are incredibly common and, depending on the type, can cause rash, itching, pain, redness, swelling, and blisters. Spider bites especially are known to cause a tiny but sometimes painful blister at the site of the injury. Fire ants and ticks can do the same.

How to Treat Insect Bites

Insect bites usually clear on their own, but there are things you can do to help ease the discomfort:

• Use an over-the-counter (OTC) hydrocortisone cream to treat itch and swelling.
• Take a nonsteroidal anti-inflammatory drug like Advil (ibuprofen).
• Take an OTC antihistamine like Claritin (loratadine) to relieve swelling and itch.
• Apply an ice pack to the bite to reduce itching and swelling.

Stasis Dermatitis

Stasis dermatitis occurs when there is poor blood circulation in the lower legs. The condition develops when valves in a vein are too weak to push blood toward the heart.

Symptoms of stasis dermatitis can include:

• Swelling of the ankles
  
• Red rash or bumps that can blister and ooze
• Itching
• Dry, scaly skin
• Varicose veins
• Darkening of the skin
  
• A heavy feeling in the legs after sitting or standing

The oozing blisters can sometimes turn into ulcers if left untreated and leave behind unsightly scars.

How to Treat Stasis Dermatitis

The treatment of stasis dermatitis almost always involves compression socks to improve circulation and prevent the pooling of blood in your legs.

Your healthcare provider may also advise you to do the following:

• Elevate the legs every two hours to reduce swelling.
• Avoid foods that are high in salt.
• Use topical corticosteroids to reduce inflammation.
• Use a topical antibiotic to treat minor infections.

Laser therapy can be used to unblock obstructions in veins that impede blood flow. Another treatment called foam sclerotherapy injects a foam substance into damaged veins to redirect blood flow to healthier veins.

Epidermolysis Bullosa Simplex

Epidermolysis bullosa simplex is a genetic disorder in which any minor injury or friction can cause the skin to blister. Mild cases affect the hands and feet, but severe cases can cause blisters to form all over the body, increasing the risk of infection and dehydration.

Over time, the condition can also cause the skin on the hands and feet to become hard and thick.

How to Treat Epidermolysis Bullosa Simplex

The treatment of epidermolysis bullosa simplex is mainly focused on protecting the skin from any friction or injury.

Your healthcare provider may also advise the following:

• Use wound dressings to protect the skin while it heals.
• Wear soft footwear that doesn’t irritate the foot or cause friction.
• Use foot antiperspirant to reduce the risk of blistering.
• Apply topical keratolytics to the soles of the feet to keep them from hardening.
• Use topical antibiotics to treat minor infections.

Summary

Various conditions can cause blisters to form on your feet. These include excess moisture and sunburn to common skin conditions like athlete's foot, allergic contact dermatitis, eczema, and psoriasis. Less common causes include stasis dermatitis caused by poor blood circulation and a rare genetic disorder called epidermolysis bullosa simplex. Even some insect bites cause blisters.

Although the treatment of foot blisters varies by the underlying cause, proper foot care and hygiene are essential irrespective of the cause.

A Word From Verywell

Most foot blisters require little or no treatment other than keeping them clean and covering them with a bandage while they heal.

However, if one or more blisters appear for no reason or either persist or worsen despite treatment, speak with your healthcare provider. They could be a sign of an undiagnosed condition in need of specific treatment.