• Perlèche (derived from the French word meaning “to lick”) is an erythematous eruption that occurs at the corners of the mouth. It is also known as angular cheilitis.

• It is sometimes seen in young patients who have atopic dermatitis (Fig. 21.16).

• Perlèche also appears in the elderly and may be caused by aging and atrophy of the muscles of facial expression that surround the mouth, which results in “pocketing” at the corners of the mouth (Fig. 21.17). These pockets become macerated and serve as a nidus for the retention of saliva, resulting in the secondary overgrowth of microorganisms such as yeasts and/or bacteria.

• In many instances, perlèche is simply a form of intertrigo, a common inflammatory condition of skin folds that occurs when opposing moist skin surfaces are in constant contact with each other.

• Other factors such as poor-fitting dentures, malocclusion, orthodontic devices, anodontia, and bone resorption may lead to drooling or vertical shortening of the face, thus accentuating the melolabial crease.

• Lip licking, thumb sucking in children, mouth breathing, and orthodontic devices are also risk factors.

• Vitamin deficiencies such as from iron, riboflavin or vitamin B12, pyridoxine, folic acid, niacin, and zinc are often blamed but rarely proved as a cause of perlèche.

• Seen in elderly men and women with fair complexions.

A squamous cell carcinoma may evolve from a solar keratosis in this area (Fig. 21.20), from leukoplakia or arise de novo inside the oral cavity (Fig. 21.21).

• Erythema multiforme minor is a self-limited eruption characterized by symmetrically distributed erythematous macules or papules, which develop into the characteristic target-like lesions consisting of concentric color changes with a dusky central zone that may become bullous.

• EM minor is not a disease but a syndrome with multiple underlying causes and associations such as drug reactions, and, most often, recurrent herpes virus infection.

• EM minor is most commonly seen in late adolescence and in young adulthood.

• Most cases are idiopathic; however, the most common precipitating cause of EM minor is recurrent labial herpes simplex virus infection; recurrences of herpes progenitalis also have been reported to precede or sometimes occur simultaneously with episodes of recurrent EM minor.

• EM major tends to be seen more often in an older age group and when there is a known or suspected cause, a drug reaction is most often implicated.

• As in EM minor, EM major is often idiopathic.

• Pyogenic granuloma (PG) is a benign vascular hyperplasia of the skin and mucous membranes that occurs most often in children and young adults.

• PGs are also seen on the lips and gums, particularly during pregnancy (granuloma gravidarum; Fig. 21.24).

• Spontaneous resolution may occur after childbirth.

• A venous lake (venous varix) is a common benign vascular neoplasm; it usually occurs in patients older than 60 years of age.

• This neoplasm is generally characterized by dark blue to purple macules or papules that may be seen on the lower lip (Fig. 21.25), face, ears, and eyelids.

• This is a common, benign, pigmented macule on the lower lip of adults.

• It is probably caused by sun exposure (Fig. 21.26), although similar lesions may be seen on the vulvae and penis and other non-sun-exposed areas.

• Typical lesions can just be observed. Suspicious lesions, including lesions showing progressive change, should be biopsied.

• If treatment is requested the macules can be frozen (cryotherapy), or removed using a laser or intense pulsed light.

• A mucous cyst (mucocele) (Fig. 21.27) is a common, mucus-filled, blister-like lesion of the minor salivary glands in the oral cavity. Some authors prefer the term mucocele since most of these lesions are not true cysts because of the absence of an epithelial lining.

• The lesions are considered to be caused by trauma to the openings of salivary glands.

• This condition is seen most commonly in infants, young children, and young adults.

• Most often observed in adults, oral fibromas are the most common intraoral neoplasm.

• Lesions likely represent reactive fibrous hyperplasia caused by trauma or local irritation.

• They are seen most often on the buccal mucosa along the plane of occlusion of the maxillary and mandibular teeth.

• Oral fibromas present as asymptomatic, smooth-surfaced, firm, solitary papules (Fig. 21.28). The diameter may vary from 1 mm to 2 cm. Ulceration caused by repeated trauma may occur.

• The clinical differential diagnosis of a fibroma includes verruca vulgaris, giant cell fibroma, neurofibroma, peripheral giant cell granuloma, mucocele, benign and malignant salivary gland tumors, as well as squamous cell carcinoma.

• Oral warts may be seen in children and adults. All are caused by the human papilloma virus (HPV) and can involve the lips (Fig. 21.29) and anywhere in the oral cavity.

• They are generally asymptomatic and are clinically similar in appearance to genital warts when they arise on mucous membranes.

• Their appearance varies. The soft, papules or nodules may be flat or cauliflower-like, and white or pinkish-white in color. The white color results from the perpetual moist environment and the lack of a stratum corneum in mucosa (Fig. 21.30).

• Most often, these lesions appear on the chin or lower jaw. The lesion often has a small indentation that results from scarring (Fig. 21.31).

• The pathologic process evolves from an intraoral abscess that forms a sinus tract that dissects subcutaneously and exits through the face or neck. The patient is usually unaware of the underlying dental etiology.

• Often diagnosed incorrectly, this lesion of dental origin often resembles a furuncle, a cyst, a pyogenic granuloma, or an ulceration.