Definition   

A vesicle is a small fluid-filled blister ranging in size from a pinpoint to 5 or 10 millimeters in diameter. As a rule, the term vesicle is used to describe a small blister, while the term bulla is used to describe a larger blister.

Common causes   

Many diseases may present with vesicles.  Some common examples include:

• Infections
• Chicken pox
• Herpes simplex (cold sores, genital herpes)
• Herpes zoster (shingles)
• Impetigo
• Contact dermatitis
• Poison ivy
• Inflammatory skin diseases
• Atopic dermatitis (eczema)
• Drug reactions
• Blistering skin diseases
• Porphyria cutanea tarda
• Dermatitis herpetiformis

Home care   

As a general rule, a physician should examine and diagnose any skin disease that includes vesicles.

Nevertheless, over the counter treatments are available for certain conditions.  For example, poison ivy may be soothed with calamine lotion and hydrocortisone cream.  Cold sores  might respond to application of local pain killers or docosanol.

Call your health care provider if   

Call your physician if any unexplained blisters appear on your skin.

What to expect   

Some vesicular eruptions can be diagnosed based entirely upon their history and appearance.  In many cases, however, additional tests are needed.  For example, the contents of a blister may be examined under the microscope or sent for bacterial or viral culture.  In particularly difficult cases, a skin biopsy may be needed to make or confirm a diagnosis.