Blisters are small, raised lesions where fluid has collected under the skin. They may be caused by an allergic reaction, burns, frostbite, or by excessive friction or trauma to the skin. Blisters may also be a symptom of a systemic illness, or of a specific skin disorder.
The thin-skinned sac of a blister contains fluid, and in most cases should not be ruptured, as rupturing can introduce infection and slow the healing process. Blisters that contain blood instead of fluid are aptly named blood blisters, and are caused by a rupture of blood vessels beneath the surface of the skin, usually due to trauma.
Causes & symptoms
Blisters can be caused by a number of conditions and environmental agents, including:
- Friction. Rubbing or pinching can cause skin irritation and blistering. Friction blisters frequently occur on the hands and feet.
- Disease. Blisters are symptomatic of skin disorders such as impetigo, incontinentia pigmenti syndrome (IPS), and pemphigus vulgaris. Blisters may also be caused by diseases such as herpes and chickenpox.
- Contact dermatitis. Skin contact with an allergen (e.g., latex, cosmetics, cleaning solutions) can trigger redness, irritation, rash, and blistering of the skin. Blisters also typically appear after skin contact with poison ivy, oak, or sumac.
- Burns. Blisters appear in cases of severe sunburn and thermal burns.
- Frostbite. Severely frostbitten skin frequently blisters.
- Trauma. Blood blisters are caused by trauma to the skin.
Other new causes of blisters are discovered by clinicians. In 2002, a report discussed how a newly
identified autoimmune blistering disease involving the mucous membranes also increased the risk of some solid cancers.
Diagnosis and treatment of most minor blisters can typically be made at home by examination of the affected area. Blisters thought to be caused by a systemic illness or disease may require professional diagnosis by a physician, dermatologist, or other healthcare professional. A medical history, physical examination, and further medical testing may be part of the diagnostic procedure.
Unless they are hindering movement or are extremely painful due to their size and/or location, blisters should not be ruptured, or "popped," as doing so can introduce bacteria into the wound. If a blister does burst, the extra skin should be left intact. Blisters that are excessively large or painful should only be punctured using antiseptic procedures, preferably by or under the direction of a qualified healthcare professional.
Treatment of blisters depends on their cause. Blisters that are symptomatic of a disease or disorder require treatment of the illness itself. Blisters caused by friction or trauma can be treated by cleansing with mild soap, applying an antiseptic, and covering the area with a sterile bandage. An herbalist, aromatherapist, or holistic healthcare professional may recommend a compress of an antiseptic or anti-microbial herb such as marigold (Calendula officinalis), thyme (Thymus vulgaris), lavender (Lavandula angustifolia), or tea tree oil (Melaleuca alternifolia).
The blister should be kept clean and the bandage changed frequently. Blood blisters should be bandaged
Conventional medicine typically follows the same procedures for treating skin blisters. A prescription or over-the-counter antiseptic ointment may be recommended to clean the blistered area.
With proper treatment, most minor blisters will heal without complication in a matter of days. More serious blisters caused by severe burns and certain diseases may produce permanent scarring or discoloration of the skin.
Friction blisters can be prevented by wearing adequate protection on the area prone to blistering. For example, long distance runners can purchase properly fitting shoes. People who work with their hands or feet can purchase special gloves or shoes and boots. For instance, in 2002, a boot company introduced safety toe footwear for occupational use with enough room for toes to move freely without rubbing against steel–toe caps.
Fair-skinned individuals who are prone to sunburn should take extra precautions to avoid skin blistering, such as using a high SPF sunscreen (at least 30 SPF) and wearing a large brimmed hat and long-sleeved, loose clothing in the sun.
Lawless, Julia. The Complete Illustrated Guide to Aromatherapy. Boston, MA: Element Books, 1997.
Minter, Stephen G. "Safety Boots to Prevent Blisters." Occupational Hazards (May 2002): 106.
Worcester, Sharon. "Risk of Solid Cancers Raised by Blistering Disease (Study of 35 Patients)." Skin &Allergy News (June 2002): 45.
Teresa G. Odle