Pemphigus vulgaris

Also called PV

Autoantibodies against desmogleins dissolve keratinocyte-to-keratinocyte adhesion WITHIN the epidermis: flaccid blisters so fragile you mostly see erosions, and the mouth is involved early and painfully.

Try the case

Deeply pigmented skin: erythema reads violaceous, grey or brown and scale looks paler by contrast

How it looks

Widespread flaccid blisters and painful denuded erosions over the trunk with extensive oral mucosal erosions; gentle lateral pressure extends the blister edge (Nikolsky positive).

Bulla Erosion Crust Confluent Truncal Generalized

Rose is the lesion, grey the pattern the lesions make, green where on the body it lives.

Across skin tones

Erosions and their post-inflammatory pigment change dominate in all skin tones; healing lesions may leave striking hyperpigmentation in deeply pigmented skin.

Don't miss

Untreated pemphigus vulgaris is potentially fatal, widespread erosion behaves like a burn: fluid loss, sepsis. This diagnosis is never watch-and-wait.

Symptoms & course

Painful mouth erosions, often the first sign by months
Skin pain more than itch
Fragile blisters that shear with friction

Diagnostic approach

Biopsy: intraepidermal (suprabasal) split with acantholysis
Direct immunofluorescence: intercellular 'chicken-wire' IgG
Anti-desmoglein 1/3 serology

Differential, and how to separate them

Bullous pemphigoid
Favours it: Tense blisters, elderly, mouth spared, itch-dominant
Against it: PV is flaccid, erosive, mucosal, and Nikolsky positive
Stevens–Johnson syndrome / toxic epidermal necrolysis
Favours it: Drug trigger, fever, targetoid dusky macules, abrupt course
Against it: PV evolves over weeks-months without a culprit drug

Management principles

Systemic corticosteroids to gain control
Rituximab and steroid-sparing agents as foundation therapy
Mucosal care and secondary-infection surveillance

Clinical pearl: Blisters below the split line (BP) are tense; blisters above it (PV) are flaccid, the physics of depth explains the whole exam-room difference.

Keep going

Try the case: It started in the mouth Compare with Bullous pemphigoid Back to the Atlas