Sore or swollen lips part 1: causes and diagnosis

Actinic cheilitis (actinic keratosis of lip, solar keratosis, solar cheilosis)

Actinic cheilitis is caused by sun over-exposure and presents with focal erythema, increased melanin production, dryness and exfoliation, while swelling and blisters appear after severe or long daily exposure to sun radiation (Figure 5).

Acute actinic (solar) cheilitis is seen in any patient regardless of age or sex as a result of over-exposure to sun radiation, while chronic actinic cheilitis usually affects middle-aged or older men with fair skin who have been constantly or frequently exposed to solar irradiation (up to 30 years) due to their outdoor activities.^11,12,13 In chronic cheilitis, there is a focal atrophy of the vermillion border intermingled with white hyperkeratotic or eroded areas covered by haemorrhagic crusts (Figure 6) and this is a potentially malignant disorder.^12,14

The presence of acanthosis or atypia in the epithelium and neovascularogenesis and elastosis in the corium are histological characteristics of actinic cheilitis,^15,16 while the spongiosis, basal cell vacuolization and oedema of the lamina propria, with lymphocytic infiltrations forming in some places as well defined lymphoid follicles, are typically seen in follicular cheilitis (see below). These follicles are composed of T helper type I, B cells and numerous dendrocytes (Langerhans cells), eosinophils and melanocytes,^{17,18,19,20,21} and are the pathognomonic histological features of other sun-induced cheilitis, such as actinic prurigo.

Actinic prurigo

This is a rare photodermatitis affecting children (Hutchinson's summer prurigo) but a rare familial form is seen mainly in adult American Indians living at high altitudes, especially in Latin America,^22,23 while a very similar condition has also been reported in China.²⁴

Follicular cheilitis is another, but rare, abnormal lip reaction to sunlight (part of the actinic prurigo spectrum disease²⁵). It is an idiopathic photodermatosis with onset at childhood (usually around 4–5 years of age) and is prevalent among high altitude living patients such as Native Americans (Indians) but also Latin Americans (Mexicans^26,27) and sporadically in patients from Asia,^28,29 Northern Europe (eg United Kingdom³⁰) and the Balkans (eg Greece).³¹ Follicular cheilitis can be the only manifestation of actinic prurigo (up to 27% of cases)¹⁷ or be seen together with skin and eye lesions.³² It presents with swelling, peeling, cracking and ulcerations covered with yellowish crusts in the vermillion area of the lower rather than the upper lip.³³ The skin shows numerous, symmetrical, discrete erythematous papules or plaques secondary to an intensive-chronic pruritus, seen usually in solar-exposed areas of the forearms, hands, face, ears, neckline, legs and feet.^28,34 The eye lesions include photophobia, pterygium, enanthema and alopecia of eyebrows.^33,35

Angular cheilitis (and angular stomatitis)

This is caused by inflammation at the commissures of the lips and mouth, respectively,³⁶ manifests as bilateral erythema and mild oedema seen typically in older people wearing dentures (with denture-related stomatitis, often candidal), followed by small ulcerations covered by white or yellow crusts (suggesting a Staphylococcus aetiology)³⁷ (Figure 7). In untreated cases, the erythema may intensify and extend onto the skin (Figure 8) with pain, burning or itching sensation followed by desquamation, granulation or even deep fissure formation.

A number of factors (infective, mechanical, nutritional or immunological) may be implicated alone or in combination. Diabetes mellitus, malignancy, human immunodeficiency virus (HlV) infection, Down's syndrome and anaemia can increase the risk of angular cheilitis.^38,39,40 Sialorrhoea, an increased production of saliva or drooling as a consequence of neurodegenerative diseases, increases the irritation and excoriation of the skin and the commissures, causing angular cheilitis.⁴¹ Cheilitis can also be seen among patients with reduced vertical facial dimension caused by overclosed dental prostheses^42,43,44 or missing teeth with neglected oral hygiene. Thus the folds around the mouth can become inflamed by Candida albicans,⁴⁵ sometimes with bacteria such as Staphylococcus aureus,⁴⁶ or β haemolytic Streptococci,^47,48 or both (>60% of cases). Diseases such as anaemia due to iron,^48,49 vitamin B12⁵⁰ or folic acid⁵¹ deficiencies are often seen in patients with angular cheilitis.

Infective agents are probably the major cause, Candida or staphylococci being isolated in many patients.^52,53,54

Unilateral lesions are unusual (Figure 9) and may be seen from trauma after long dental treatment or flossing,⁵⁵ or may be infective, such as in herpes zoster or secondary syphilis (split macules) (Figure 10).

In the edentulous patient who does not wear a denture as a normal consequence of the ageing process or in a patient with the wrong prosthesis, the upper lip overhangs the lower at the angles of the mouth, producing a fold that keeps a small area of skin macerated. Maceration of the commissural epithelium brought on by habitual licking as a nervous tic, sucking on objects by children, and seepage of saliva into deep skin folds at the corners of the mouth, especially in the elderly, are all contributory (perleche).

Cheilitis is common in Down syndrome as the large tongue and the constant dribbling (characteristic findings) possibly being contributory factors, along with immune deficiency and sometimes with candidiasis.

Nutritional deficiencies of riboflavin, folate, iron, zinc and general protein malnutrition have often been incriminated in angular cheilitis or stomatitis, but are rare. Riboflavin deficiency produces smooth, shiny red lips associated with angular stomatitis, and this combination has been called cheilosis^49,56,57

Crohn's disease or orofacial granulomatosis may be found in a very small minority.⁵⁸ Outbreaks of acute pustular and fissured cheilitis may occur rarely in children, particularly if they are ill-nourished and, in some cases, streptococci or staphylococci have appeared to be causative.⁵⁹ Angular stomatitis, often with ulcerations, is a common feature in acrodermatitis enteropathica, an autosomal dominant disorder that results from an inability to absorb sufficient amounts of zinc from the diet.⁶⁰

Angular cheilitis associated with candidiasis may also be a manifestation of an underlying immunological deficiency such as diabetes or HIV disease.

Atopic dermatitis involving the face is often associated with angular cheilitis. The incidence of angular cheilitis appears also to be increased in seborrhoeic dermatitis but any association with other skin diseases is probably fortuitous. Rare causes are contact cheilitis at the commissures or the presence of sinuses of developmental origin at the angles of the mouth.

Atopic cheilitis

This is a limited form of atopic dermatitis which presents with dryness, redness and scaling of the vermillion border and perioral skin.^61,62 Patients with atopic cheilitis have a more severe form when one or both their parents also suffer⁶³ or if it is associated with other disseminated neurodermatoses.⁶⁴

Cheilitis simplex (‘chapping’ of the lips)

Cheilitis simplex is the most common form of cheilitis and mainly occurs when lips are exposed in extreme weather conditions or in the licking habit. Chapped lips are thus often seen among long distance runners,⁶⁵ soldiers during summer or winter exercises,⁶⁶ and also among young patients with allergic rhinitis.⁶⁷

Cheilitis simplex is characterized by a diffuse erythema, cracks and fissures formation, superficial ulcerations accompanied by a burning sensation or itching on both lips (Figures 11 and 12). The lips become sore and scaly and the affected person tends to lick the lips, or to pick or chew at the scales, which may aggravate the condition.

Contact or allergic cheilitis

This is an inflammatory reaction of the lips provoked by the irritant or allergic sensitizing action of chemical agents, initiated by contact or by a phototoxic effect. Irritant contact cheilitis is rare and caused by a chronic lip-licking habit or drugs intake, while allergic contact cheilitis is more common and characterized by a hypersensitivity lip reaction to various dental materials, foods or cosmetics.^68,69

Contact allergic cheilitis is an exogenous type of eczematous cheilitis and appears with erythema, exfoliation, vesicles or bullae formation which easily break and leave painful ulcerations in the lips within 24 to 72 hours, after their exposure to various allergens found in foods, preservatives, cosmetics or dental products (eg spearmint oil in toothpastes, mouthwashes)^{70,71,72,73,74,75,76,77} (Figure 13).

A large number of substances have been incriminated but lipsticks or lip salves cause most cases. Lipstick cheilitis is sometimes confined to the vermillion border but more often extends beyond it. The offending lipstick may have been adopted only recently or may have been in regular use for many years. Exacerbations develop a few hours or over a day after the application. Tartar-control toothpastes, mouthwashes, a plethora of different dental materials, foods, flavourings and cane reed instruments are among the many other known causes (Table 3).

Cheilitis may also be induced by sucking items such as hair clips, pencils⁷⁸ or nail varnish.

The mouthpieces of musical instruments are another rare cause of cheilitis.⁷⁹ The metal mouthpieces of trumpets and other ‘brass’ instruments can cause contact dermatitis, lacerations and acne mechanica. Cheilitis due to prolonged playing of woodwind instruments has also been reported and is thought to be due to mechanical factors⁸⁰ or hypersensitivity and irritant reactions to the Arundo donax cane reed mouthpiece or to Machaerium scleroxylum.

There may be persistent irritation and scaling or a more acute reaction with oedema and vesiculation. The lips may show erythema, oedema, vesicles, weeping, crusts, scales, or fissures (Figure 13).