Bullous systemic lupus erythematosus
BSLE is caused by autoantibody formation against the noncollagenous type 1 and 2 (NC1 and NC2) components of Collagen VII (Col7), causing disruption and separation of the structure of the dermal-epidermal junction, with subsequent complement deposition, and recruitment of neutrophils. Col7 is the major component of the anchoring fibrils in the cutaneous basement membrane zone (BMZ).
BSLE is typically a disease of young adulthood, affecting those between 20 and 40 years of age, but it has also been reported in children and older adults. Similar to the sex predilection of SLE, BSLE affects more women than men.
BSLE typically presents as an abrupt onset of tense vesicles and blisters on an erythematous background or on normal skin. Urticarial plaques may be present. Face, trunk, and extensor surfaces of limbs are the most commonly involved body sites, but other body locations can be involved. BSLE may clinically mimic a range of autoimmune diseases, most commonly bullous pemphigoid (BP). Epidermolysis bullosa acquisita (EBA)-like, linear IgA bullous dermatosis (LABD)-like, and dermatitis herpetiformis (DH)-like presentations have also been noted.
Photodistribution or photoexacerbation has been reported. Intraoral blisters and erosions and blistering along the lip vermillion can be seen. Esophageal involvement with sloughing of the esophageal mucosa has rarely been reported.
M32.9 – Systemic lupus erythematosus, unspecified
239889005 – Bullous systemic lupus erythematosus
Differential Diagnosis & Pitfalls
- Nonimmunologic bullous eruptions in SLE include bullous presentations of acute cutaneous lupus erythematosus and discoid lupus erythematosus (DLE) that may be seen secondary to a severe interface dermatitis. A toxic epidermal necrolysis (TEN)-like presentation of acute SLE is a rare phenomenon, and this resembles typical TEN.
- Epidermolysis bullosa acquisita (EBA) – The target antigen in EBA is Col7, as in BSLE, which shows immunoreactant deposition on the floor of a salt split indirect immunofluorescence (IIF) specimen. EBA can be distinguished from BSLE by lack of underlying SLE and other softer measures such as a more chronic course and lower responsiveness to dapsone.
- Linear IgA bullous dermatosis (LABD) – LABD typically presents with annular plaques with peripheral vesiculation or a "crown of jewels." LABD is distinguished by salt split skin with immunoreactant (IgA) on the roof or epidermal side of the split skin.
- Anti-p200 pemphigoid – Clinical presentation of anti-p200 pemphigoid varies. Anti-p200 pemphigoid can be a histologic mimic of BSLE with IIF on salt split to the floor or dermal side of the BMZ. The target antigen is laminin gamma-1 instead of Col7.
- Dermatitis herpetiformis (DH) – DH typically presents with intensely pruritic vesicles / bullae and erosions in the scalp, elbows, forearms, knees, and buttocks. DH can also be distinguished by histology and direct immunofluorescence (DIF) with IgA deposition in the dermal papillae, lack of other features of SLE, negative ANA, and the presence of antigliadin and transglutaminase-2 / 3 antibodies.