Symptom Checker: Symptoms & Signs Index
Medical Author: Melissa Conrad Stöppler, MD
Blisters are small raised areas that are filled with fluid and located in the superficial layer of the skin. They look like bubbles on the surface of the skin. Although they are often caused by irritation or friction (such as with a poorly fitting shoe), blisters can also represent disease processes. Blisters can accompany some types of skin rashes and inflammatory conditions, including certain autoimmune diseases. Depending upon the cause of the blisters, blisters may occur singly or in groups. In contrast to abscesses and boils, which are collections of inflammatory fluid found deep in the tissues, blisters are found in the most superficial layer of skin.
Small fluid-filled blisters are medically known as vesicles. Bullae (singular = bulla) are blisters that are larger than 1 cm across.
Health concern on your mind? Visit the Symptom Checker.
Fauci, Anthony S., et al. Harrison's Principles of Internal Medicine. 17th ed. United States: McGraw-Hill Professional, 2008.
Causes of Blisters
In This ArticleAllergy Article
- Allergy facts
- What does an allergy mean?
- What causes allergies?
- Who is at risk and why?
- What are common allergic conditions, and what are allergy symptoms and signs?
- Hay Fever
- Allergic Eyes
- Allergic Eczema
- Allergic Shock
- Where are allergens? Everywhere
- In the air we breathe
- In what we ingest
- Touching our skin
- Injected into our body
In This ArticleBed Bugs Article
- Bed bugs facts
- What are bed bugs? What do bed bugs look like?
- Where are bed bugs found?
- What about bed bugs in hotels?
- How are bed bugs spread?
- What are the symptoms and signs of bed bug bites?
- What is the treatment for bed bug bites?
- How do I detect a bed bug infestation in my home?
- How do I get rid of bed bugs in the home?
- What about prevention of bed bug bites?
In This ArticleBullous Pemphigoid Article
- What is bullous pemphigoid?
- What are symptoms of bullous pemphigoid?
- How is bullous pemphigoid diagnosed?
- What is the treatment for bullous pemphigoid?
- What is the prognosis of bullous pemphigoid?
In This ArticleBurns (First Aid) Article
- Introduction to burns
- How are burns classified?
- What is the significance of the amount of body area burned?
- How important is the location of a burn?
- What about electrical burns?
- What about chemical burns?
- First aid for burns
In This ArticleChickenpox (Varicella) Article
- What is chickenpox? What causes chickenpox?
- How does chickenpox spread?
- What are chickenpox symptoms and signs?
- What are treatment options for chickenpox?
- What are the possible complications of chickenpox?
- Can chickenpox be prevented with a vaccine?
- Chickenpox At A Glance
In This ArticleCuts, Scrapes and Puncture Wounds Article
- Cuts, scrapes (abrasions), and puncture wounds facts
- What is the best way to care for a cut or scrape?
- Who should seek medical care for a cut?
- What are the signs and symptoms of a wound infection?
- How are puncture wounds different?
- Will I need a tetanus shot for a cut, scrape, or puncture wound?
In This ArticleEczema Article
- Eczema facts
- What is eczema?
- What are the causes of eczema?
- What are risk factors for eczema?
- What are eczema symptoms and signs in babies, children, and adults?
- What are the different types of eczema?
- How is eczema diagnosed?
- What is the treatment for eczema?
- Can eczema be prevented?
- What are the possible complications of eczema?
- What is the prognosis (outlook) for eczema?
In This ArticleFolliculitis Article
- Folliculitis facts
- What is folliculitis? What are folliculitis symptoms and signs? What does folliculitis look like?
- Who develops folliculitis?
- What are the causes of folliculitis?
- How is folliculitis diagnosed?
- What else could folliculitis look like?
- What are common types of folliculitis?
- What is hot tub folliculitis or Jacuzzi folliculitis?
- What is razor burn folliculitis?
- What is pseudofolliculitis barbae?
- Is folliculitis curable? Is folliculitis contagious?
- What are possible complications of folliculitis?
- How is folliculitis treated?
- What is the prognosis (outlook) with folliculitis?
- How do I prevent folliculitis?
In This ArticleGenital Herpes In Women Article
- What are sexually transmitted diseases (STDs)?
- What is genital herpes?
- What causes genital herpes?
- What are genital herpes symptoms and signs?
- How is genital herpes diagnosed?
- What is the treatment for genital herpes?
- How can genital herpes be prevented?
- What is the prognosis (outlook) for genital herpes?
- Where can people get more information about genital herpes?
- Genital Herpes At A Glance
Herpes Simplex Infections (Cold Sores, Non-Genital) Herpes simplex infections are common and when they appear around the mouth and lips, people often refer to them as "cold sores"...learn more »In This ArticleHerpes Simplex Infections (Cold Sores, Non-Genital) Article
- Herpes simplex infections (nongenital cold sores) facts
- What are herpes simplex infections?
- What causes cold sores?
- What makes herpes (cold sores) recur?
- How do cold sores spread?
- What are the signs and symptoms of cold sores?
- What is primary oral herpes?
- What does recurrent herpes look like?
- How long do cold sores last?
- What are the possible complications of oral herpes (cold sores)?
- What other conditions can look like oral herpes (cold sores)?
- What is angular stomatitis?
- What are canker sores?
- How is oral herpes diagnosed?
- What is the treatment for cold sores, are there any home remedies, and what medications are used?
In This ArticleImpetigo Article
- Impetigo facts
- What is impetigo? What causes impetigo?
- What are the types of impetigo, and what are impetigo symptoms and signs? What does impetigo look like?
- Is impetigo contagious?
- How is impetigo diagnosed?
- What is the treatment for impetigo?
- What are possible complications of impetigo?
- Will impetigo leave scars?
- Can impetigo be prevented?
In This ArticleLichen Sclerosus Article
- What is lichen sclerosus?
- Who gets lichen sclerosus?
- What are lichen sclerosus symptoms and signs?
- What causes lichen sclerosus?
- How is lichen sclerosus diagnosed?
- What is the treatment for lichen sclerosus?
- Can people with lichen sclerosus have sex?
- Is lichen sclerosus related to cancer?
- What kind of doctor treats lichen sclerosus?
- Where can I find more information about lichen sclerosus?
In This ArticlePoison Ivy Article
- Poison ivy, oak, and sumac facts
- What causes the rash? How do I identify poison ivy, oak, and sumac?
- What are the signs and symptoms of the poison ivy rash?
- Is a rash from poison ivy, oak, and sumac dermatitis contagious?
- What are risk factors for poison ivy, oak, and sumac dermatitis?
- How is the dermatitis of poison ivy, oak, and sumac diagnosed?
- What is the treatment for poison ivy, oak, and sumac dermatitis?
- What are complications for poison ivy, oak, and sumac dermatitis?
- What is the prognosis (outlook) for poison ivy, oak, and sumac dermatitis?
- How can contact with poison ivy, oak, and sumac be prevented?
- What should people do if they are exposed to a poisonous plant?
In This ArticleRash Article
- Rashes facts
- What are noninfectious, common rashes localized to a particular anatomical area?
- How are common skin rashes diagnosed?
- Scaly patches of skin produced by fungal or bacterial infection
- Widely distributed rashes affecting large portions of the skin
- What is the treatment for a rash?
In This ArticleScabies Article
- Scabies facts
- What is scabies? What causes a scabies infestation?
- How do you get scabies?
- Can you catch scabies from a dog or cat?
- What are risk factors for scabies?
- What does a scabies rash look like? What are scabies symptoms and signs?
- What does scabies feel like?
- How is a scabies infestation diagnosed?
- What are treatment options and home remedies for a scabies infestation?
- Are cases of scabies often misdiagnosed?
- What are possible complications of scabies?
- Can a scabies infestation be prevented?
- In what special situations can scabies be more easily spread?
- What is Norwegian or crusted scabies?
- What is the prognosis (outlook) for scabies?
Sexually Transmitted Diseases in Men (STDs in Men) Sexually transmitted diseases, or STDs, are infections that are transmitted during any type of sexual exposure, including...learn more »In This ArticleSexually Transmitted Diseases in Men (STDs in Men) Article
- Sexually transmitted diseases (STDs) in men facts
- What are STDs and how can their spread be prevented?
- Diseases associated with genital lesions
- Genital herpes
- Lymphogranuloma venereum (LGV)
- Human papillomavirus (HPV)
- Diseases associated with urethritis
- Systemic STDs
- Human immunodeficiency virus (HIV)
- Hepatitis B
- Hepatitis C
- Human herpes virus 8 (HHV-8)
- Ectoparasitic infections
In This ArticleShingles Article
- Shingles facts
- What is shingles? What causes shingles?
- What are shingles symptoms and signs? How long does shingles last?
- How long is shingles contagious?
- How is shingles diagnosed?
- What is the treatment for shingles? Should I visit my health care professional?
- What are the complications of shingles?
- What is postherpetic neuralgia?
- Can shingles be prevented with a vaccine?
- What are potential side effects of the shingles vaccine?
- Is shingles dangerous in pregnant women?
Spider Bites (Including Black Widow and Brown Recluse) The majority of spiders in the United States are harmless. Two exceptions include the black widow spider and the brown recluse...learn more »In This ArticleSpider Bites (Including Black Widow and Brown Recluse) Article
- Are spider bites dangerous?
- What are the symptoms of spider bites?
- Black widow spider bite symptoms (picture of black widow)
- Brown recluse spider bite symptoms (picture of brown recluse spider)
- What should you do if you are bitten by a spider?
- What should you do if you are bitten by a black widow or brown recluse spider?
- Spider Bites At A Glance
In This ArticleSunburn (Sun Poisoning) Article
- Sunburn facts
- What is sunburn?
- Can sunburn cause permanent damage?
- What is UV light and where are UV rays most intense?
- What are the symptoms of sunburn?
- What are the symptoms of severe sunburn (sun poisoning)?
- Sunburn pictures
- What first-aid measures should be taken with sunburn?
- What is the treatment for sunburn?
- Are there any home remedies to treat sunburn?
- Is a follow-up visit with a physician necessary?
- Why does the skin tan after exposure to UV rays?
- Who is most susceptible to sunburn?
- Can diseases cause a heightened sensitivity to UV rays?
- Can medications increase sensitivity to sunburn?
- What kinds of skin cancer can UV rays cause?
- How can sunburn and skin cancer be prevented?
- How do sunscreens work?
- What is SPF?
- What is the best way to apply sunscreen?
- Do sunscreens expire?
- Can antioxidants protect against sunburn?
Other Causes of Blisters
Symptoms & Signs A-Z List
Find out what women really need.