What causes blisters?

A blister can be a symptom of a variety of disorders, diseases or conditions including infection, inflammation, trauma, allergic reaction, and other abnormal processes. Some causes may be relatively mild, such as blisters on the feet from ill-fitting shoes or blisters on the hands from working with garden tools. Other conditions require prompt medical care, such as an infectious disease or scalding from boiling water.

Infections that cause blisters

Blisters can be caused by infectious diseases including:

  • Bacterial skin infection, such as cellulitis or impetigo, which are commonly caused by staphylococcal or streptococcal bacteria

  • Chickenpox (varicella-zoster virus infection)

  • Herpes simplex virus infection, which causes cold sores (fever blisters) and genital herpes

  • Infected hair follicle

  • Shingles (reactivation of the chickenpox virus)

  • Syphilis

  • Yeast (fungal) infection

Trauma or injuries that cause blisters

Blisters can be due to irritation of the skin or trauma including:

  • Chafing or friction, such as from ill-fitting shoes

  • Chemical, electrical or heat burn

  • Frostbite

  • Insect bites, such as chigger bites

  • Radiation burn

  • Sunburn

Other disorders that cause blisters

Blisters can be due to a variety of other diseases, disorders, and conditions including:

  • Adverse drug reaction
  • Allergic skin reaction
  • Bullous pemphigoid (a possible autoimmune disorder)
  • Contact dermatitis, such as a reaction to poison ivy
  • Dermatitis herpetiformis (no known cause, but this disorder is linked to gluten sensitivity)
  • Erythema multiforme (allergic reaction in response to a drug, infection, or other illness)
  • Paraneoplasia (benign skin changes indicating cancer elsewhere)
  • Pemphigus vulgaris or other bullous (blistering) diseases
  • Porphyria cutanea tarda (an enzyme deficiency)
  • Scabies (mite infestation)

    Questions for diagnosing the cause of blisters

    To diagnose the underlying cause of blisters, your doctor or licensed health care practitioner will ask you several questions about your symptoms. Providing complete answers to these questions will help your provider in diagnosing the cause of your blisters:

    • When and where did the blisters first appear?

    • Have you had similar blisters before?

    • Do the blisters seem to be spreading? Where?

    • Do you have any other symptoms, such as fever or body aches?

    • Have you been in recent contact with any unusual substances or environments, such as exposure to allergens, chemicals, or poison ivy, or are you taking new medications or supplements?

    What are the potential complications of blisters?

    Complications associated with a blister can be progressive and vary depending on the underlying cause. Because blisters can be due to a serious disease, failure to seek treatment can result in complications and permanent damage. It is important to contact your health care provider when you develop an unexplained blister or group of blisters, even if you do not have other symptoms. Once the underlying cause is diagnosed, following the treatment plan outlined by your doctor can help reduce any potential complications including:

    • Bacterial or fungal infection of the skin (cellulitis) or spread of an existing infection

    • Chronic pain or discomfort
    • Open sores and lesions

    • Permanent change in skin texture and scarring

    • Permanent skin discoloration


    1. Vesicles. Medline Plus, a service of the National Library of Medicine National Institutes of Health. www.nlm.nih.gov/medlineplus/ency/article/003939.htm.
    2. Bullous pemphigoid. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/ency/article/000883.htm.
    3. Porphyria. a service of the National Library of Medicine National Institutes of Health. www.nlm.nih.gov/medlineplus/ency/article/001208.htm
    4. Weedon D. Weedon's Skin Pathology, 3rd ed, Philadelphia: Elsevier Limited, 2010.

    What are blisters?

    A blister is a collection of clear fluid trapped between or beneath the top layer of skin, the epidermis. Blisters, which are often called “water blisters,” often break open and the fluid inside is released onto the skin. Blisters, also known as vesicles, can occur in all age groups and populations.

    A blood blister is a specific type of blister that is due to damage to blood ve... Read more about blistersintroduction


    What other symptoms might occur with blisters?

    Blisters may occur with other symptoms, which vary depending on the underlying disease, disorder or condition. Common symptoms can include a burning sensation, pain, rash and itching. Potential symptoms that may accompany a blister include:

    Medical Reviewer: William C. Lloyd III, MD, FACS Last Annual Review Date: Aug 23, 2013 Copyright: © Copyright 2014 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

    This Article is Filed Under: Skin, Hair and Nails

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