DR13.1-2 | Vesiculobullous Lesions — Glossary

The loss of adhesion between keratinocytes, causing them to round up and separate; the histological hallmark of pemphigus, producing an intra-epidermal split.

A pain-relieving oral rinse used to ease painful oral erosions so the patient can maintain oral intake and nutrition.

The proportion of skin involved by erosions; extensive involvement (roughly above 20-30%) signals significant fluid-loss risk and the need for IV fluids and urgent referral.

A hemidesmosomal transmembrane protein and a principal autoantigen in bullous pemphigoid; circulating anti-BP180 antibodies aid diagnosis and monitoring.

An intracellular hemidesmosomal plaque protein that is a second autoantigen in bullous pemphigoid.

A short course of systemic corticosteroid (e.g. prednisolone ~1 mg/kg/day) started to slow active blistering before specialist review; not a substitute for definitive specialist-led immunosuppression.

A large fluid-filled blister, conventionally greater than 0.5 cm in diameter; may be flaccid or tense depending on the depth of the split.

Lateral extension of an intact bulla when downward pressure is applied to it; positive when an intra-epidermal cleavage plane allows easy spread, as in pemphigus.

A sub-epidermal autoimmune blistering disease of the elderly caused by IgG against BP180/BP230, with tense bullae, usual sparing of the mouth, and a negative Nikolsky's sign.

An intensely itchy, IgA-mediated sub-epidermal blistering disease with grouped vesicles on extensor surfaces, associated with coeliac disease; a differential for autoimmune blistering.

A desmosomal adhesion protein binding keratinocytes together; desmoglein 3 and 1 are the autoantigens in pemphigus vulgaris.

A junction that mechanically links adjacent keratinocytes; its disruption by anti-desmoglein antibodies causes the intra-epidermal split of pemphigus.

The gold-standard test on perilesional skin that visualises bound antibody: intercellular fish-net IgG/C3 in pemphigus versus a linear basement-membrane band in bullous pemphigoid.

A raw, denuded area left after a superficial blister roof shears off; widespread painful erosions are typical of pemphigus vulgaris.

A thin-roofed, easily ruptured blister that collapses under its own weight, indicating a high (intra-epidermal) split; characteristic of pemphigus vulgaris.

The status of body water and salts; extensive skin erosions leak fluid and protein like partial-thickness burns, so balance must be monitored and replaced.

A junction anchoring the basal keratinocytes to the basement membrane; its components BP180 and BP230 are the autoantigens in bullous pemphigoid.

A serum test that detects circulating antibodies against skin antigens, complementing DIF for diagnosis and monitoring.

Shearing-off of the superficial epidermis when lateral pressure is applied to skin; positive in pemphigus vulgaris (intra-epidermal weakness) and negative in bullous pemphigoid (intact sub-epidermal junction).

A wound dressing that does not stick to the raw surface, used to protect eroded skin without enlarging it; adhesive tape must be avoided on fragile perilesional skin.

An intra-epidermal (suprabasal) autoimmune blistering disease caused by IgG against desmoglein 3 (and desmoglein 1), with flaccid bullae, common oral involvement, and a positive Nikolsky's sign.

Apparently normal skin immediately adjacent to a lesion; the correct site for eliciting Nikolsky's sign and for direct immunofluorescence biopsy.

The supportive and protective care a first-contact doctor provides — wound and oral care, fluid/electrolyte and nutritional support, infection control, and bridging treatment — before referring a blistering patient to dermatology.

Findings that mandate prompt specialist referral — confirmed or strongly suspected autoimmune blistering disease, extensive erosions, or failure to maintain oral intake.

Infection of denuded skin by bacteria entering through erosions; the leading cause of death in extensive blistering disease, requiring surveillance and prompt treatment.

A toxin-mediated superficial blistering disease, mainly in children, that produces a positive Nikolsky's sign; another Nikolsky-positive mimic to distinguish by context.

An immunosuppressant (e.g. azathioprine, mycophenolate mofetil, cyclophosphamide) added to corticosteroids to control disease while reducing steroid dose and toxicity.

A drug-induced, life-threatening mucocutaneous reaction with epidermal detachment and a positive Nikolsky's sign driven by keratinocyte necrosis (not acantholysis); an important Nikolsky-positive mimic.

A drug-induced, life-threatening mucocutaneous reaction with epidermal necrosis and a positive Nikolsky's sign; an important Nikolsky-positive mimic of pemphigus.

Sliding, sideways pressure applied across the skin surface (rather than straight down); the correct technique for eliciting Nikolsky's sign.

A firm, dome-shaped blister that resists rupture because of a thick full-thickness epidermal roof, indicating a deep (sub-epidermal) split; characteristic of bullous pemphigoid.

A rapid bedside cytology test from the floor of a fresh erosion; shows rounded acantholytic (Tzanck) cells in pemphigus.

A small fluid-filled blister, conventionally up to 0.5 cm in diameter.

A group of skin diseases characterised by fluid-filled blisters (vesicles up to 0.5 cm, bullae above 0.5 cm); the autoimmune forms arise from antibodies attacking skin adhesion proteins.