Approach to Blistering Skin Conditions Dr Wei Jing Loo Assistant Professor University of Western Ontario LHSC/ SJHC

Objectives  Competent in defining bulla & vesicle  Demonstrate ability to describe blistering skin conditions  Able to provide a list of differential diagnosis for blistering eruptions  Demonstrate understanding of basic etiology/ pathogenesis of common blistering eruptions

Bulla • An elevated lesion that contains clear fluid • A large blister ≥ 10 mm in diameter

Vesicle • An elevated lesion that contains clear fluid • A small blister less than 10 mm in diameter

General approach  History  Examination  Investigations

History  Age  Previous medical history  Drug history  Onset/ Duration of blisters  Associated symptoms

Examination  Site/ distribution of blisters  Localised/ generalised  Associated systemic signs  Examine mucus membranes  Don’t forget SCALDA

Investigations  Blood work  Skin scraping/ nail clipping  Allergy testing  Skin biopsy

Causes of Blistering  Infection  Inflammatory  Mechanical  Drug induced  Metabolic  Autoimmune blistering diseases

Infection  Bacteria  Viral  Fungal

Bullous impetigo

Chicken pox

Tinea pedis

Inflammatory  Acute eczema  Contact dermatitis  Phototoxic reaction  Insect bite reaction

Dyshidrotic dermatitis

Acute bullous contact dermatitis

Phytophotodermatitis

Arthropod bites

Mechanical  Friction  Burns  Cold injury

Friction blisters

Burns

Frost bite

Drug induced (will be covered in another lecture)  Erythema multiforme  Stevens-Johnson Syndrome  Toxic Epidermal Necrolysis (will be covered in another lecture)

Metabolic  Porphyria cutanea tarda  Diabetes

Porphyria

Bullous diabeticorum

Immunobullous disorders  Bullous pemphigoid  Pemphigus  Dermatitis Herpetiformis

Bullous pemphigoid  Patients over 60 years old  Rarely in children  No racial or ethnic predilection  males = females

Histology – H&E

Bullous pemphigoid - IMM F

Bullous pemphigoid  Self limited  Good prognosis  Remission after 5 to 6 years  May persist for > 10 years

Pemphigus Mediterranean descent.  Mean age of onset 50 to 60 years old.  Both sexes affected equally.  Common in Jews/ Mediterranean descent.

Pemphigus

Pemphigus vulgaris

Histology – H&E

Pemphigus - IMM F

Bullous pemphigoid Pemphigus

Pemphigus  Mortality rate 6%  Main cause of death – infection  Immunosuppressives a contributing factor  If patient survives >5 years after inception of disease, outcome is usually excellent

Dermatitis herpetiformis  2nd to 4th decade of life  2x as common in males  Gluten sensitive enteropathy  Small bowel biopsy

Dermatitis herpetiformis  Severe burning & itching  Precedes lesions 8 to 12 hours

Laboratory investigations  Blood tests  Antiendomysium antibodies  Tissue transglutaminase levels  Antireticulin antibodies  Antigliadin antibodies  Skin biopsy + direct IMF

Dermatitis herpetiformis - treatment  Sulfones Dapsone  Sulfapyridine  Gluten free diet

Summary  Definition of bulla and vesicle  Describe blistering skin eruptions  Systematic approach to blistering skin conditions based on causes/ etiology