8.3 Oral Mucosal, Lip, Genital Mucosal & Perianal (Proctological) Disease

Key Takeaways

  • Minor aphthous ulcers are under 1 cm and heal in 7 to 14 days without scarring, whereas major aphthae exceed 1 cm, last weeks, and scar.
  • The International Criteria for Behçet Disease give 2 points each for oral aphthosis, genital aphthosis, and ocular lesions and 1 point each for skin, neurological, and vascular lesions and a positive pathergy test, with 4 points diagnostic.
  • Oral leukoplakia is a clinical diagnosis of a white patch of questionable cancer risk, and persistent leukoplakia or any erythroplakia needs biopsy to assess dysplasia.
  • Apremilast is approved in the EU for oral ulcers of Behçet disease in adults who are candidates for systemic therapy.
  • A chronic anal fissure is usually in the posterior midline, and a lateral or multiple fissure should prompt a search for Crohn disease, HIV, syphilis, tuberculosis, or cancer.
Last updated: September 2026

8.3 Oral Mucosal, Lip, Genital Mucosal & Perianal (Proctological) Disease

Normal Variants of the Oral Mucosa

VariantFeatures
Fordyce spotsSmall yellow ectopic sebaceous glands on lips and buccal mucosa
Geographic tongue (benign migratory glossitis)Changing red patches with white borders; linked to psoriasis and atopy
Fissured tongueDeep grooves; seen in Melkersson-Rosenthal and Down syndromes
Black hairy tongueElongated filiform papillae, after antibiotics, smoking, or poor hygiene
LeukoedemaGrey-white buccal film that disappears when stretched
ToriBony swellings of the palate or mandible

Recurrent Aphthous Stomatitis

TypeSize and Course
Minor (about 80%)Under 1 cm, round with a yellow base and red halo, heals in 7–14 days without scarring
MajorOver 1 cm, deep, lasts weeks, heals with scarring
HerpetiformDozens of tiny ulcers that may merge

Look for underlying causes: iron, vitamin B12, and folate deficiency; coeliac disease and inflammatory bowel disease; Behçet disease; HIV; cyclic neutropenia; PFAPA syndrome in children (periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis); and drugs, especially nicorandil (large painful ulcers) and NSAIDs.

Treatment: topical corticosteroids (mouthwash, paste, or spray), chlorhexidine or benzydamine mouthwash, and correcting deficiencies. Colchicine or dapsone are used for recurrent severe disease.

Behçet Disease

A variable-vessel vasculitis, most common along the ancient Silk Road (Turkey, the Middle East, East Asia) and linked to HLA-B*51.

International Criteria for Behçet Disease (ICBD, 2014):

FeaturePoints
Oral aphthosis2
Genital aphthosis2
Ocular lesions (uveitis, retinal vasculitis)2
Skin lesions (pseudofolliculitis, erythema nodosum)1
Neurological manifestations1
Vascular manifestations (thrombosis, aneurysms)1
Positive pathergy test (optional)1

A score of 4 or more indicates Behçet disease. Genital ulcers usually affect the scrotum or labia and often scar.

Treatment (EULAR recommendations): colchicine for mucocutaneous disease and erythema nodosum; apremilast (EU-approved for oral ulcers of Behçet disease); topical steroids; azathioprine, TNF-alpha inhibitors, or interferon-alpha for eye, neurological, and vascular disease.

White and Red Lesions

LesionFeaturesAction
Pseudomembranous candidiasisCreamy plaques that wipe off, leaving red mucosaAntifungals; look for inhaled steroids, diabetes, dentures, immunosuppression, HIV
Oral lichen planusLacy white striae, often bilateral on buccal mucosaSee lichen planus section
Frictional keratosisWhite area at a site of chronic rubbingRemove the cause and review
Oral hairy leukoplakiaCorrugated white plaques on the lateral tongue, do not wipe offEBV; suggests HIV or other immunosuppression
White sponge naevusSoft white folds from childhoodBenign; keratin 4 or 13 mutations
LeukoplakiaA white patch that cannot be explained by any other conditionBiopsy to grade dysplasia; stop tobacco and alcohol; long-term review. Proliferative verrucous leukoplakia has a high cancer risk
ErythroplakiaRed velvety patchHighest risk of dysplasia or carcinoma; always biopsy

Oral squamous cell carcinoma: risk factors are tobacco, alcohol, betel quid, and immunosuppression; HPV mainly drives oropharyngeal cancer. Any ulcer that has not healed within about 3 weeks needs biopsy.

Pigmented, Blistering, and Other Oral Lesions

  • Pigmented: amalgam tattoo, oral melanotic macule, smoker's melanosis, Addison disease, Peutz-Jeghers syndrome, drugs (antimalarials, minocycline), and oral melanoma (palate and gingiva).
  • Blistering and erosive: pemphigus vulgaris (often starts in the mouth), mucous membrane pemphigoid (desquamative gingivitis), erythema multiforme (haemorrhagic crusting of the lips), SJS/TEN, paraneoplastic pemphigus, and erosive lichen planus.
  • Viral: primary herpetic gingivostomatitis; hand, foot, and mouth disease (coxsackievirus A16 or enterovirus A71; the coxsackie A6 variant is more widespread and can cause later onychomadesis); herpangina.
  • Burning mouth syndrome: burning pain with normal mucosa, mainly in postmenopausal women. First exclude deficiencies, candidiasis, dry mouth, and contact allergy; topical clonazepam is one treatment option.
  • Dry mouth (xerostomia): Sjögren syndrome, drugs (anticholinergics, antidepressants), and head and neck radiotherapy.

Lip Disorders

DisorderFeatures
Angular cheilitisFissuring at mouth corners from Candida or S. aureus, deep folds, dentures, iron or B-vitamin deficiency
Actinic cheilitisScaly, blurred vermilion border of the lower lip from chronic sun exposure; premalignant. Treatment: 5-fluorouracil, imiquimod, photodynamic therapy, laser, or vermilionectomy
Lip squamous cell carcinomaMostly lower lip, in smokers and outdoor workers; higher metastatic risk than most skin SCC
Contact cheilitisLipsticks, toothpaste flavours, fragrance; patch test
Exfoliative cheilitisPersistent peeling, often from lip licking or picking
Cheilitis granulomatosaPersistent swelling; exclude Crohn disease and sarcoidosis

Non-Infectious Genital Mucosal Disease

  • Lichen sclerosus of the vulva and penis (see the anogenital section): porcelain-white atrophic plaques, scarring, and a risk of squamous cell carcinoma; treat with very potent topical steroids.
  • Zoon (plasma cell) balanitis: a shiny orange-red patch on the glans of uncircumcised older men; plasma cells on biopsy; improves with hygiene and topical steroids, and circumcision is curative. Zoon vulvitis is the rare female form.
  • Other causes: psoriasis (no scale on the glans), eczema, fixed drug eruption, Behçet disease, lichen planus, and intraepithelial neoplasia (see the HPV section).

Perianal and Anal Disorders (Proctology)

DisorderKey FeaturesManagement
HaemorrhoidsInternal (graded I–IV by prolapse) cause painless bleeding; thrombosed external haemorrhoids are acutely painfulFibre and fluids; banding or surgery for internal; early excision of a thrombosed external haemorrhoid
Anal fissureTearing pain on defecation with bright red blood; usually posterior midline; sphincter spasmStool softeners, topical glyceryl trinitrate or diltiazem, botulinum toxin, lateral internal sphincterotomy. Lateral or multiple fissures: consider Crohn disease, HIV, syphilis, tuberculosis, or cancer
Perianal abscess and fistulaPainful swelling, discharge; fistulas are common in Crohn diseaseSurgical drainage; MRI; manage Crohn disease
Pruritus aniChronic perianal itchLook for secondary causes: poor or excessive hygiene, contact allergy (topical anaesthetics, fragrances), psoriasis, lichen sclerosus, Candida, haemorrhoids, and threadworm (tape test; treat the household with mebendazole)
Perianal streptococcal dermatitisBright red, sharply defined perianal rash in young children, with pain on defecationSwab for group A streptococcus; oral penicillin
Anal warts and anal intraepithelial neoplasiaSee the HPV section—
Pilonidal sinusMidline natal cleft sinus with abscesses; part of the follicular occlusion groupSurgical treatment
Test Your Knowledge

A 30-year-old Turkish man has recurrent painful oral aphthae and scrotal ulcers that have scarred, plus acneiform pseudofolliculitis on his back. An eye examination is normal. What is his ICBD score, and does he meet the criteria for Behçet disease?

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D
Test Your Knowledge

A 60-year-old smoker has a persistent white patch on the floor of the mouth that cannot be wiped off and has no obvious cause. What is the most appropriate management?

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B
C
D
Test Your Knowledge

A 28-year-old woman has recurrent anal pain and bleeding. Examination shows two fissures, one on each lateral side of the anal canal, and a skin tag. What is the most important next step?

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B
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D
Test Your Knowledge

A 72-year-old uncircumcised man has a well-defined, shiny, orange-red patch on the glans that has been present for 2 years. Biopsy shows a dense plasma cell infiltrate. What is the definitive treatment?

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D