Name That Lesion

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Name That Lesion
Is it a cold sore? A canker sore? A fever blister? An apthous ulcer?

If you aren’t always certain – you are not alone. Two groups of oral lesions – recurrent herpes simplex and recurrentapthous ulcers may be difficult to distinguish. To aid you in you diagnosis, this dental byte presents:
(1) Why You May Get Confused
(2) An Overview of the Two Garden Varieties
(3) A Terminology Reference Chart


(1) Why You May Get Confused:

The use and misuse of Colloquial Terminology:

What one person calls a “cold sore”, another person may call a “canker sore” another person may call a “fever blister” and yet another may call an “apthous ulcer”.Note: The “garden variety” form of recurrent herpes simplex when it is extraoral is referred to as:

Herpes Labialis = cold sore = fever blister

Note: The “garden variety” or common form of apthous ulcer is always intraoral and is referred to as:

Minor Apthous = canker sore

Some Similarities Between the Lesions Do Exist:

Herpes simplex lesions and apthous ulcer lesions do share some characteristics. They both:

are very common
are recurrent
are painful
form ulcers
repeatedly develop at same site
have similar precipitating causes

Less common varieties Muddy the Water:

For example:

Intraoral herpes simplex ulcers can easily be confused with herpetiform and minor apthous ulcers.


(2) Overview of the two garden variety lesions:

Differential diagnosis:

Location Propensity?:
(a) Recurrent Herpetic Labialis: Garden variety herpetic ulcers are usually extraoral. (vermilion border of lip, perioral skin)
(b) Recurrent Minor Apthous: Garden variety apthous ulcers are usually intraoral. (movable oral mucosa such as: tongue, floor of mouth soft palate, buccal and labial mucosa)

Preceeded by Vesicles?:
(a) Recurrent Herpetic Labialis: All herpetic ulcers are preceeded by vesicles.
(b) Recurrent Minor Apthous: Apthous ulcers are never preceeded by vesicles.

What’s a vesicle? The term vesicle comes from the latin word for “little bladder.” Common in viral infections, vesicles are fluid filled elevations less than 1 cm in diameter. The epithelial lining quickly breaks down giving rise to an ulcer.

Note: Intraoral HSV is almost always on “bound” oral mucosa. lntraoral apthous ulcers are almost always on “movable” oral mucosa.

Therapeutic considerations:

(a) Recurrent Herpetic Labialls

caused by – herpes simplex virus
treatment protocol: Topical anti viral ointment
Rx: 5% acyclovir ointment
Disp: 15 gm tube
Sig: Apply to lesions 6X a dayNote: Herpes lesions are very contagious

(b) Recurrent Minor Apthous

unknown cause – many different theories/ one of the least understood oral diseases
treatment protocol: Topical steroid
Rx: Kenalog in Orabase 0.1%, topical analgesics
Disp: 5 gm tube
Sig: Apply to lesion after each meal and at bedtime

Note: Apthous ulcers are not contagious


(3) Terminology Reference Chart

Herpes Simplex Lesions & Apthous Ulcer Lesions

[Terminology Reference Chart]