Widespread painful oral erosions preceding skin blisters

§Chief complaint

Painful sores throughout the mouth for 2 months, cannot eat

§Medical & dental history

• 01No relevant drug history
• 02Weight loss of 6 kg due to pain
• 03Unable to brush due to pain; heavy plaque accumulation

§Clinical examination

• 01Multiple ragged, irregular erosions on the buccal mucosa, soft palate and gingiva
• 02Intact blisters rare; positive Nikolsky sign
• 03Desquamative gingivitis
• 04Two flaccid bullae on the scalp appearing last week

§ figuresFigures (1)

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§Differential diagnosis

§Final diagnosis

Pemphigus vulgaris with mucosal-dominant presentation

Fragile blisters that rupture immediately, a positive Nikolsky sign, and a suprabasal split with acantholysis on histology, plus intercellular IgG in a fishnet pattern on direct immunofluorescence, separate pemphigus from the subepithelial pemphigoid group.

§Investigations

• 01Perilesional incisional biopsy for H&E and a separate specimen in Michel medium for direct immunofluorescence
• 02Indirect immunofluorescence and anti-desmoglein 1 and 3 ELISA
• 03Baseline FBC, glucose, bone density before steroids

§Treatment plan

• 01Systemic corticosteroids (prednisolone) as first-line
• 02Steroid-sparing immunosuppression (azathioprine or mycophenolate); rituximab increasingly first-line
• 03Topical high-potency steroid for oral lesions plus antifungal cover
• 04Nutritional support and analgesia; dermatology co-management

§Histopathology report

Suprabasal intraepithelial split with acantholytic Tzanck cells and a row-of-tombstones basal layer. Direct immunofluorescence: intercellular IgG and C3 in a fishnet pattern.

§Follow-up & outcome

• 01Oral lesions healed by 8 weeks on prednisolone and rituximab
• 02Steroid tapered; on maintenance immunosuppression
• 03Regular monitoring for steroid complications

§Clinical pearls / learning points

• 01Oral lesions precede skin lesions in most cases of pemphigus vulgaris — dentists often diagnose it first.
• 02Always take a second perilesional biopsy for direct immunofluorescence; H&E alone is not enough.
• 03Untreated pemphigus vulgaris was historically fatal; prompt referral is essential.

§Related diseases

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