The working diagnosis of SC is usually straightforward. It devolves from correlating a thoroughly discerned history with clinical findings in an at-risk patient. The presence of concurrent AK on sun-exposed areas (face, neck, bald scalp, ears) reinforces the clinical impression. Several other conditions affecting the lip may mimic SC and should be considered in the differential diagnosis. Table 2 provides a comprehensive list of differential diagnoses and associated characteristics.2,3,39-53
Table 2. Differential Diagnoses Associated with Solar Cheilosis.
Chronic cheek biting/chewingFactitial shaggy lesions commonly observed on buccal mucosa, lateral tongue, lips. Historical clues and direct observation for habit.
Exfoliative cheilitis2,3Unusual condition, typically affects young women, often attributed to factitial self-induced trauma. Hyperkeratosis and desquamation limited to lip vermilion, possible yellow hyperkeratotic or thick hemorrhagic crusts, no underlying physiologic disorder noted. Proposed psychogenic cause.
Contact dermatitis2,3Any age involved, scaling and erythema may be limited to lip vermilion, both upper and lower lips typically involved. Careful history necessary to elucidate possible causes.
Irritant– Extremes of dry, cold, windy, hot, humid may lead to sloughing.
Allergic– Possible causes include toothpaste (flavorings, preservatives), tarter control toothpastes (pyrophosphate compounds) and lipsticks and lip balms (oxybenzone, lanolin, preservatives).
Phototoxic– Numerous medications (tetracyclines, sulfamethoxazole, chlorthiazide, bupropion, ibuprofen, diuretics, many others). Psoralens in citrus fruits may react with UV light to induce cheilitis.
Lichen planus40,41Common mucocutaneous disorder, female predominance, 4th – 6th decade, may wax and wane, variable discomfort. Characteristic lacy striations, papules, plaques.
Histological: Dense subepithelial band like infiltrate of T-cells, basal cell layer liquefaction, disruption of the basement membrane.
Lichenoid drug reaction42Clinical appearance indistinguishable from LP. Careful historical analysis necessary to determine inciting agent. Diagnosis validated by lesion resolution after discontinuance of suspected agent (and reappearance on reexposure to inciting agent).
Histological: Essentially identical to LP.
Candidiasis (angular cheilitis)Most typically noted at commissures, mixed red/white lesions with ulceration or crusts. White curds or plaques that wipe off leaving an erythematous base.
Histological: Evidence of candidal hyphae and spores noted on specimen (smears, tissue biopsy).
Cheilitis glandularis43,44Rare, chronic inflammatory conditions manifesting minor salivary gland hypersecretion and ductal ectasia. Lips are swollen, nodular, and everted and associated minor salivary gland secretion is thick and sticky. Cause is unknown.
Histological: Nonspecific with possible glandular hyperplasia and ductal ectasia.
Erythema multiforme45,46Characteristic abrupt onset with pain. Most common in adolescents/young adults and frequently associated with prior HSV outbreak. Variable oral presentation with intraoral bullae and erosions, often with crusting lesions on lips and cutaneous target lesions.
Histological: Nonspecific evidence of inflammation; immunofluorescent staining for perivascular IgM, IgG, C3 may be noted, but are nonspecific.
Pemphigus vulgaris47,48Median age of onset 50+ with slight female predominance. Oral lesions (blisters, erosions, and ulcers) occur in over 85% of cases and often precede occurrence of cutaneous lesions. Typical sites affected are buccal mucosa, tongue, floor of mouth, and palate.
Histological: Suprabasilar splitting and clefting. Characteristic immunofluorescent staining of intercellular deposits of IgG and C3 throughout the epithelium.
Discoid lupus erythematosus49Five– 20% of cases progress to SLE. Positive ANA titers unusual. Typical oral lesions presents as a red atrophic center with peripheral border of radiating hyperkeratotic striae.
Histological: Granular or homogenous bands of immunoglobin (IgG and IgA) in the BMZ
Graft Versus Host Disease50History of allogeneic stem cell transplantation. Clinical appearance similar to LP. Frequent involvement of salivary gland tissues leads to xerostomia.
Histological: Virtually identical to LP
Systemic lupus erythematosus49Oral lesions are often painless and occur in about 19% of cases. Positive ANA titers in 95% - 100% of cases. Variable oral presentation (discoid, plaques, ulcers, lichen planus-like lesions).
Histological: Granular or homogenous bands of immunoglobin (IgG and IgA) in the BMZ
Plasma cell cheilitis51Rare inflammatory disorder manifesting glistening red lower lip, fissuring, ulceration, tenderness.
Histological: Band-like infiltrate of plasma cells in upper dermis
Cheilitis granulomatosa (Miescher’s cheilitis)52,53Rare idiopathic condition manifesting episodic nontender enlargement of one or both lips. Lips may feel soft, firm or nodular. Onset typical in young adults with no racial or gender predilection. Many consider a monosymptomatic form of Melkerson-Rosenthal syndrome.
Histological: Lymphedema and noncaseating granulomas noted in lamina propria.
Because of the progressive nature of SC, the presence of a chronic lesion on the lip vermilion mandates a biopsy.1 The spectrum of histological findings associated with clinical SC include hyperkeratosis, parakeratosis/orthokeratosis, epithelial atrophy, vasodilation, inflammatory infiltrates, solar elastosis, atypia, dysplasia, SCC-in-situ (SCIS) and invasive SCC.1,7,21,22,39,54-62 In one study, 10.34% of the patients had mild, 27.57% had moderate, and 62.07% had severe biopsy-proven dysplasia.22