Immunobullous Disease Flashcards
What are some blistering conditions that are NOT autoimmune in nature?
- Bullous diabeticorum
- Coma blister
- Bullous impetigo
- Edema blister
- Bullous small vessel cutaneous vasculitis
- Bullous Fixed drug rxn
- Exuberant bug bites/ bed bug bites
- Cutaneous mastocytoma
- Epidermolysis Bullosa
What is this?
Bullous diabeticorum- common in long-standing diabetes (common on feet and lower legs)
While lesions typically heal spontaneously within 2-6 weeks, they often recur in the same or different locations. Secondary infections may also develop; these are characterized by cloudy blister fluid and require a culture.
What is this?
Coma blister from pressure
What is this?
Bullous impetigo (common in infants)
What is this?
Bullous small vessel cutaneous vasculitis (palpable, and non-blanching- morbilliform do blanch) and may have bleeding
What is this?
Bullous Fixed drug rxn
What is this?
Cutaneous mastocytoma (commonly seen in kids)
What is this?
Epidermolysis bullosa (have this from birth)
What are some autoimmune blistering diseases?
- Bullous pemphigoid
- Pemphigus vulgaris
- Dermatitis herpitformis
- Epidermolysis bullosa acquisita, IgA pemphigus, Bullous SLE, Linear IgA bullous dermatosis
Normal Skin histology
Describe bullous pemphigoid
Autoimmune disease typically affecting older (68-82) adults (women more than men) where autoantibodies form to hemidesmosomes in basal cells that anchor the epidermis to the dermis
What are the specific antigens targeted in bullous pemphigoid?
BP 180 and BP 230 (in hemidesmosomes= tense blisters)
How does Bullous pemphigoid present?
Often starts with a very itchy, urticarial rash (may be confused for a drug interaction) that develops into tense blisters that may or may not have surround erythema and are USUALLY SYMMETRICALLY DISTRIBUTED
What is this?
Blisters of bullous pemphigoid- tense, may or may not have surrounding erythema/urticaria base and are usually symmetric
Tense means they will not break/pop easily
Bullous pemphigoid
Bullous pemphigoid
BP
Tense blister (=intact)
What are the variants of bullous pemphigoid?
- Mucous membrane pemphigoid (scarring eye involvement that can lead to blindness or oral lesions +/- skin lesions) (below)
- Gestational pemphigoid or ‘herpes gestationis”
Describe Gestational pemphigoid or ‘herpes gestationis”
BP arsing in pregnant women, usually during 2ND TRIMESTER that can be associated with preterm labor or low weight babies
Remits postpartum, but can recur in successive pregnancies
How is BP diagnosed?
Skin biopsy for routine studies and direct immunofluorescence (DIF) studies showing a band of IgG and C3 at the dermal-epidermal junction
May or may not find Abs in blood
How is BP treated?
long term systemic steroids and/or immunosuppression (BP usually lasts several years, then remits)
Describe Pemphigus vulargis
rare autoimmune disease affecting all ages (mean 50-60 yo) and especially those of Mediterranean or Ashkenazi Jew descent that is characterized by autoantibodies to parts of desmosomes
What are the specific targets of autoantibodies in pemphigus vulgaris?
desmoglein 1 and 3
Describe the histology of PV
‘row of tombstones’ appearance with intraepidermal split (within epidermis) and signs of acantholysis (individual cells losing attachments)
Describe the immunoflourescence of PV
Intracellular (netlike-between keratinocytes) IgG and C3
How does PV present initially?
Often stars with painful erosions in the mouth or gums
How does PV progress?
Blisters may or may not develop on the skin and if they do are **flaccid and easily broken**. Lesions are most common on the head, chest, back, and intertriginous areas and can be painful
Mucuous membrane involvement may be extensive, involving all mucosa, the larynx, esophagus, and conjunctiva
PV
PV
How is PV diagnosed?
skin biopsy and direct immunoflourescence
How is PV treated?
Needs long-term Tx with steroids and immunosuppression (fatal up to 70% of time if untreated mostly due to sepsis)
What are the variants of PV?
- Pemphigus foliaceus- a superficial pemphigus endemic in BRAZIL with Abs against desmoglein 1 (top of cells) and scale crusts resembling corn flakes (front of card)
- Paraneoplastic pemphigus (below)
What is Dermatitis herpetiformis?
Autoimmune bullous disease linked to celiac disease thought to be in response to chronic stimulation of gut mucosa
What Abs are formed in dermatitis herpetiformis?
- IgA to tissue transglutaminase (t-TG) (in gut)
- t-TG cross reacts with epidermal transglutaminase (e-TG) in skin
What are transglutamines?
cytoplasmic Ca-dependent enzymes that catalyze crosslinks between glutamine and lysine and are improtant in forming insoluble protein polymers (necessary to create barriers and stable structures, inlcuding blood clots, hair and skin)
Difference between DH and celiac disease
DH antigen is EPIDERMAL tranglutaminase and celiac disease antigen is tissue transglutaminase
Not all patients with celiac disease have DH, but all DH pts. are assumed to have enteropathy
Patient pop for DH?
Avg age of onset is between 30-40 more commonly in men with Hx of GI distress
Is there a genetic predisposition for those with DH?
Yes, HLA-DQ2 and HLA-DQ8
How does DH present?
Pts present with intensely itchy rash (may or may not see vesicles) with symmetric distribution (elbows, butt, knee, scalp, and neck) and MUCOSAL involvment is RARE
Management of DH?
Strict adherence to gluten free diet. Dapsone can be used to control itch VERY RAPDILY but doesnt treat the gut (stil need to be on gluten free diet)
What is this?
Poison Ivy- look for vesicles in a line
Associations with DH?
other autoimmune conditions including thyroid disease, diabetes, CT disorders AND
increased risk of lymphoma
