What are the causes and treatment options for lip discoloration?

Lip Discoloration: Causes and Treatment

Lip discoloration requires immediate evaluation to exclude oral melanoma through full excisional biopsy, as this carries significant mortality risk if not diagnosed early. 1

Diagnostic Approach

Critical Warning Signs Requiring Urgent Biopsy

When evaluating any brownish or pigmented lip lesion, you must assess for melanoma using the ABCDE criteria 1:

• Asymmetry of the lesion
• Border irregularity
• Color heterogeneity (multiple shades within one lesion)
• Diameter >5-7mm
• Dynamics (evolution or recent change in appearance)

Perform a full excisional biopsy with 2mm margin using a surgical knife—never use laser or electrocoagulation as these destroy tissue needed for diagnosis. 1 Progressive change in lesion size is a major indication for immediate excision, particularly in elderly patients with new pigmented lesions. 1

Physical Examination Requirements

Complete the following systematic evaluation 1:

• Examine the entire skin surface, not just the lips
• Palpate all regional lymph nodes (preauricular and cervical)
• Document exact lesion size, color characteristics, border definition, and any ulceration, bleeding, or inflammation
• Assess for associated systemic findings

Major Causes of Lip Discoloration

Blue/Cyanotic Discoloration

Methemoglobinemia presents as blue-gray or lavender discoloration of the lips, buccal mucosa, nose, and cheeks that does not improve with supplemental oxygen. 2

Key diagnostic features 2:

• MetHb levels typically 20-30% when blue discoloration is visible
• Present from birth in congenital cases (Type I)
• May be accompanied by headaches, tachycardia, mild dyspnea
• Type II includes severe neurological deficits (microcephaly, dystonia, developmental delay)
• Pulse oximetry shows unexpected/discordant results

Brown/Dark Pigmentation

Peutz-Jeghers Syndrome (PJS) is characterized by dark brown or blue-brown melanotic macules 1-5mm in size. 2

Diagnostic criteria 2:

• 94% of patients have pigmentation on the vermilion border of the lips
• 66% have buccal mucosa involvement (key distinguishing feature from simple freckles)
• Pigmentation typically appears in infancy and may fade in late adolescence
• Requires hamartomatous polyps PLUS at least 2 of: labial melanin deposits, family history, small bowel polyposis
• Autosomal dominant inheritance with STK11/LKB1 gene mutation

Critical distinction: Unlike freckles, PJS pigmentation is always present on buccal mucosa and profusely around nostrils and mouth. 2

Laugier-Hunziker syndrome differs from PJS by 2:

• Progressive acquisition in young/middle-aged adults (not infancy)
• Possible conjunctival pigmentation
• Longitudinal melanonychia of digits
• No gastrointestinal polyps

Yellow Discoloration

Smoker's mustache presents as acquired yellow discoloration of upper lip hair in elderly smokers with several years of tobacco use. 3

Clinical features 3:

• Originates centrally over philtrum, expanding laterally
• May be accompanied by yellow-brown thumbnail/fingernail discoloration
• Asymptomatic; patients often unaware or unconcerned
• Management: smoking cessation and/or hair removal

Other Causes

Actinic cheilitis presents as grayish-whitish discoloration with blunted demarcation between mucosa and cutaneous lip—this is a precancerous condition representing early squamous cell carcinoma. 4

Port-wine vascular malformations cause tissue enlargement (macrocheilia) with associated discoloration. 5

Treatment Approach

For Suspected Malignancy

Immediate full excisional biopsy with 2mm margin is mandatory—partial biopsy is inadequate. 1 Use surgical knife, not laser or electrocoagulation. 1

For Peutz-Jeghers Syndrome

No treatment eliminates the pigmentation itself. Management focuses on 2:

• Surveillance for gastrointestinal polyps and associated cancer risk
• Genetic counseling for STK11/LKB1 mutation
• Regular screening for breast and gynecologic cancers in females

For Actinic Cheilitis

Erbium laser resurfacing (2940-nm) is highly effective for 4:

• Clinically prominent actinic cheilitis
• Biopsy-proven actinic cheilitis
• Treatment of entire lip following squamous cell carcinoma excision

Alternative options include topical fluorouracil, imiquimod, cryotherapy, or surgical vermillionectomy. 4

For Methemoglobinemia

Treatment depends on type and severity 2:

• Type I (isolated methemoglobinemia): Generally no treatment needed; patients are otherwise well
• Acquired methemoglobinemia: Remove offending agent
• Symptomatic cases: Consider methylene blue or ascorbic acid

For Cosmetic Concerns

Hyaluronic acid fillers can address lip volume and contour issues but do not treat discoloration itself. 6 These should be injected above the orbicularis oris muscle using 27-30 gauge needles, 0.2-0.5 mL per quadrant. 6

Critical Pitfalls to Avoid

• Never delay biopsy in elderly patients with new or changing pigmented lesions—melanoma incidence peaks at age 65. 1
• Never perform partial biopsy of suspected melanocytic lesions; always do full excisional biopsy with margins. 1
• Never assume absence of family history excludes PJS—30-70% of cases are sporadic. 7
• Never use laser or electrocoagulation for diagnostic biopsy as this destroys tissue architecture. 1
• Never ignore buccal mucosa pigmentation—this distinguishes PJS from benign freckles and requires gastrointestinal evaluation. 2