logo Blistering skin diseases

Itchy skin disease

Blistering skin diseases


Describe key points

Key points

  • Blisters are accumulations of fluid within or under the epidermis.
  • Diagnosis depends on the site of the intercellular split.
  • Epidermolysis bullosa results in blisters and erosions due to minor trauma.
  • Immunobullous disorders are diagnosed by skin biopsy and direct immunofluorescence.
  • Immunobullous disorders may require high dose corticosteroids and immunosuppressives for control.
  • Bullous pemphigoid affects the elderly.
  • Bullous pemphigoid results in an itchy rash and subepidermal bullae.
  • Dermatitis herpetiformis presents as vesicles and crusts on scalp, elbows and knees.
  • Dermatitis herpetiformis is associated with gluten sensitive enteropathy.
  • Pemphigus causes oral and cutaneous erosions due to intraepidermal bullae.
  • Pemphigus is potentially life-threatening.
Site of blister Characteristics Differential diagnosis Appearance
Subcorneal Very thin roof breaks easily Impetigo, miliaria, SSSS


Intra-epidermal Thin roof ruptures to leave denuded surface Acute eczema, varicella, herpes simplex, pemphigus


Subepidermal Tense roof often remain intact Bullous pemphigoid, dermatitis herpetiformis, erythema multiforme, TEN, friction blisters

Systemic lupus erythematosis

Inherited blistering diseases

Epidermolysis bullosa (EB) refers to a group of inherited disorders in which there are mutations in specific keratin proteins (EB simplex), hemidesmosomes (junctional EB), anchoring filaments or type VII collagen (dystrophic EB). Minor trauma results in blisters and erosions, the split site and severity depending on the specific defect.

Varying presentations of Epidermolysis bullosa

Immunobullous eruptions

There are at least 9 distinct immunobullous diseases due to autoantibodies directed at differing components of the desmosome complex. Skin biopsy and direct immunofluorescence are diagnostic and there may be detectable circulating skin antibodies. A specialist dermatologist should manage these disorders as high dose corticosteroids and immunosuppressive medication may be required for control.

Bullous pemphigoid is the most common immunobullous disease and affects the elderly. It may start off as dermatitis or a non-specific pruritic rash that eventually develops subepidermal bullae.

Varying presentations of bullous pemphigoid

Dermatitis herpetiformis results in intensely itchy vesicles and crusts on scalp, elbows, buttocks, knees and elsewhere. IgA autoantibodies to reticulin, gliadin and/or endomysium may be detected in serum. It is invariably associated with gluten-sensitive enteropathy although this may be asymptomatic. Dapsone rapidly controls itching and blistering but gluten-free diet is required long term for control.

Dermatitis herpetiformis

Pemphigus has various subtypes caused by pathogenic IgG antibodies to intraepidermal cell adhesion molecules. Pemphigus vulgaris is potentially fatal; it usually presents with oral ulceration followed by widespread denudation.

Oral pemphigus

Pemphigus vulgaris

Pemphigus foliaceus