What laboratory tests are ordered for cheilitis?

Laboratory Testing for Cheilitis

Order a complete blood count (CBC), iron studies (serum iron, ferritin, TIBC), vitamin B12, and folate levels as initial screening tests for cheilitis, particularly when systemic nutritional deficiencies are suspected. 1, 2

Initial Laboratory Workup

Essential Screening Tests

• CBC with differential to evaluate for anemia, which commonly presents with cheilitis as a manifestation of iron or vitamin B12 deficiency 2
• Iron studies including serum iron, ferritin, and total iron-binding capacity (TIBC) to assess for iron deficiency anemia 2
• Vitamin B12 and folate levels as deficiencies in these vitamins are well-established causes of cheilitis 2
• Fasting blood glucose to screen for diabetes, which predisposes to infectious cheilitis (particularly angular cheilitis with candidal infection) 3

Infectious Workup (When Indicated)

For angular cheilitis or suspected infectious etiology:

• Fungal culture or KOH preparation from the affected area to identify Candida species 4, 2
• Bacterial culture if bacterial superinfection is suspected, particularly with crusting or purulent drainage 4
• HIV antibody testing in patients with recurrent or refractory angular cheilitis, as immunosuppression is a known precipitating factor 4

Additional Testing Based on Clinical Presentation

For Contact Dermatitis Suspicion

• Patch testing is the definitive diagnostic test for allergic contact cheilitis and should be performed when history suggests exposure to potential allergens (lipsticks, toothpaste, dental materials, medications) 5, 6
• Common allergens to test include fragrance mix, balsam of Peru, nickel, colophony, and specific ingredients in lip care products 6

For Chronic or Atypical Cases

• Biopsy of the affected lip tissue is indicated for:
  • Actinic cheilitis to exclude dysplasia or squamous cell carcinoma 5, 2
  • Granulomatous cheilitis to confirm non-caseating granulomas 5, 2
  • Plasma cell cheilitis to identify plasma cell infiltration 2
  • Any chronic lesion not responding to empiric treatment after 2-4 weeks 3, 1

For Systemic Disease Evaluation

When cheilitis appears as part of a broader clinical picture:

• Antinuclear antibody (ANA) and extractable nuclear antigens (ENA) if lupus erythematosus is suspected 5, 2
• Serum immunoglobulins and complement studies if immunodeficiency is considered 3
• Syphilis serology (RPR or treponemal-specific test) for oral lesions with unclear etiology 7

Clinical Algorithm for Laboratory Testing

Step 1: Start with CBC, iron studies, B12, folate, and fasting glucose in all patients with persistent cheilitis (>2 weeks duration) 1, 2

Step 2: Add infectious workup (fungal/bacterial cultures, HIV testing) if angular cheilitis is present or if patient has risk factors for immunosuppression 4

Step 3: Perform patch testing if history suggests contact allergen exposure or if initial workup is negative 5, 6

Step 4: Proceed to biopsy if:

• Lesions persist despite treatment of identified deficiencies
• Actinic changes are present (chronic sun exposure, fair skin, age >50)
• Unilateral or asymmetric involvement raises concern for malignancy
• Granulomatous features (persistent swelling) are noted 1, 5, 2

Common Pitfalls to Avoid

• Do not assume all cheilitis is simply "dry lips" - approximately 25% of cases are due to allergic contact dermatitis requiring specific allergen identification 6
• Do not overlook nutritional deficiencies - iron, B12, and folate deficiencies are frequently missed causes of persistent cheilitis 2
• Do not delay biopsy in actinic cheilitis - this is a potentially malignant condition requiring histologic evaluation to exclude dysplasia or carcinoma 5, 2
• Do not forget to test for diabetes in patients with recurrent angular cheilitis, as hyperglycemia predisposes to candidal infection 3
• Do not order extensive autoimmune panels routinely - reserve ANA and related testing for cases with clinical features suggesting systemic lupus or other connective tissue disease 5, 2