What is the difference between a vesicle and an oral ulcer?


We are going to review the differences between vesicles and ulcerations, two types of lesions found in an oral cavity. If you look at this oral mucosa decision tree for oral lesions, many of these lesions are classified as vesiculobullous or vesicular ulcerative conditions.

The Difference between a Vesicle and an Ulcer

In order to explore the scope of ulcerative conditions in later articles, let’s start with the difference between a vesicle and an ulcer.

What is a vesicle?

A vesicle is an elevated, fluid-filled lesion covered by epithelium.  The fluid may accumulate either within the epithelium (intraepithelial) or below the epithelium (subepithelial).  It is a small bulla, less than or equal to 1 centimeter in diameter.

What is an ulcer?

An ulcer is a defect or disruption in the continuity of the epithelial component of the oral mucosa so that a depression exists.  This is often covered by a fibrinopurulent membrane.  A vesicle may eventually lose the overlying epithelium and then present as an ulceration.

Differential Diagnosis of a Vesicle and Oral Ulcer

Mouth ulcers pictures. Differential diagnosis of a vesicle and an ulcer in the oral cavity.
Histological picture of a vesicle and ulcer in the oral cavity.

The left photomicrograph shows fluid accumulation within the stratified squamous epithelium, which causes an ovoid defect.  Also, note the presence of inflammation in the underlying connective tissue.

As you can imagine, the superior aspect of the vesicle, the thin compromised portion of the epithelium is very fragile and friable.  When this is subject to trauma it disintegrates and the overlying epithelium is lost. The result is an ulceration.

The right photomicrograph shows the absence of stratified squamous epithelium centrally.  At either edge is hyperplastic and hyperparakeratotic stratified squamous epithelium. The ulcer bed is composed of granulation tissue, inflammatory cells, and a lot of congested blood vessels.

Now that we understand the difference between a vesicle and an ulcer, we’ll look at more complex ulcerative conditions. In the next article, we’ll cover diagnosing, treating, and reviewing histological differentials of pemphigus vulgaris.