Some causes of a cluster of blisters are herpes, burns, and shingles. Cold sores and fever blisters are caused by an extremely common virus called herpes simplex. Severe burns can also cause a cluster of blisters and often require a health professional’s expertise. In addition, shingles is a virus much like chickenpox that is capable of producing blisters. Impetigo, a skin infection common in children, is also responsible for some blister clusters.
The herpes simplex virus affects most people and is the most likely cause of a cluster of blisters in adults. Studies estimate that anywhere from 65% to 95% of adults have the virus, with a good portion of children acquiring it by age five. The virus spreads when people come into contact with open blisters or objects contaminated by blister fluid. It is also possible for a person to have the virus, show no symptoms, and spread it to other people by kissing. Many people are not even aware they have the virus because the symptoms are so mild.
A cluster of blisters can also be caused by second degree burns. First degree burns are the least severe and usually do not develop blisters. With third degree burns, there may not be enough skin left to blister. Second degree burns are fairly common, and can be caused by hot water, bumping a hot oven rack, or coming into brief contact with fire. Large second degree burns or burns on certain areas of the body, such as the genitals, face, and hands, should be treated like third degree burns with the injured person seeking professional medical help as soon as possible.
Shingles is a virus that is similar to chickenpox but that primarily affects older adults. It looks like chickenpox. It starts as a rash but progresses into blisters. A major difference between chickenpox and shingles is the location of the blisters. Chickenpox appears all over the body, usually with the blisters spread out, clustering only by chance. Shingles most often appears on only one side of the body, and the blisters are always clustered because they arise from a rash.
Impetigo is a skin infection caused by the bacterium responsible for strep throat. This bacterium is normally present on the skin and enters the body through bites, scratches, and other injuries. Impetigo rarely occurs in more than a few patches, and it is usually not dangerous. Some children may experience complications such as kidney failure and permanent scarring, however. Impetigo can be cured with antibiotic creams or, in severe cases, antibiotic pills.