Blisters and emergencies Flashcards
Describe what is meant by bullous pemphigoid [1]
It is caused by antibodies agaisnt which basement membrane proteins? [2]
Which patients is it commonly found in?
In frail patients
Autoimmune blistering condition
Antibodies against basement membrane proteins which are key components of hemidesmosomes
* BP 180
* BP 230
Which neurological conditions is Bullous Pemphigoid associated with? [3]
Which medications are Bullous Pemphigoid associated with? [2]
Neurological disease (that cause frailty)
* Stroke
* Dementia
* Parkinson’s Disease
Drugs:
* PD-1 Inhibitors (used in the treatment of metastatic melanoma)
* Gliptins (diabetic medication)
Describe the clinical manifestations of Bullous Pemphigoid [5]
- Severe itch
- Pre-bullous rash
- Large tense bullae and erosions on rupture
- Milia in healed areas
- Multple, large tense blisters - that leave eriosions after they burst
- Mucosal lesions uncommon
NB: top right shows the erosion after a blister has gone
What is a classic differentiating feature between pemphigoid and pemphigus? [2]
Bullous pemphigoid:
- mouth is usually spared
- blisters are more tense
Pemphigus vulgaris:
- Mouth commonly involved
- blisters commonly burst
Describe the topical treatments [4] and systemic therapy [5] used to treat Bullous Pemphigoid
Topical Treatments
* Super potent topical steroid
* Non adhesive dressings
* Potassium per manganate soaks
* Pop large blisters
Systemic therapy
* Antihistamines
* Tetracycline antibiotic vs oral steroid (BLISTER trial)
* Methotrexate
* Mycophenolate Mofetil
* Biologic therapy - Rituxumab
Describe how you investigate for bullous pemphigoid
Punch biopsy:
- immunofluorescence shows IgG and C3 at the dermoepidermal junction
Complications associated with BP? [4]
Secondary infections:
* Staphylococcus aureus and Pseudomonas aeruginosa are the most common organisms
* risk of sepsis is significant due to disrupted skin integrity
Side effects from treatment:
- significant corticosteroid use: osteoporosis, diabetes mellitus, hypertension, glaucoma or cataracts
Elderly-related complications::
- Cognitive impairment has been linked with bullous pemphigoid
Increased risk of cardiovascular disease and stroke
Young person x Erosions x Mucosal ulceration =
Pemphigus Vulgaris
NB: erosions are previous flaccid blisters
Describe the pathophysiology of Pemphigus Vulgaris [1]
Autoimmune blistering condition
- Autoantibodies to Desmoglein-3 (and sometimes also Desmoglein-1) which are found in desmosomes
- The autoantibodies belong to the IgG class, specifically IgG4
Describe the clinical features of pemphigus vulgaris [+]
- Mucosal involvement usually precedes skin involvement – mouth + genitals: oral lesions are common and often present as the initial clinical feature.
- Thin-walled flaccid blisters filled with clear fluid
- Rupture easily
- Itchy, painful erosions
- Painful ! :( - epidermis has gone and exposing the dermis
- Often lose weight (due to mouth ulcers stopping eating)
Which drugs can induce PV? [2]
Penicillamine
ACE-inhibitors
PV can be a pareneoplastic disease of which cancers? [2]
Lymphomas
Castleman disease
Dx of Pemphigus Vulgaris ?
Punch/incisional biopsy of:
* Lesional skin for H&E
* Peri-lesional skin direct immunofluorescence
- Fishnet pattern of intercellular IgG and C3 deposits within the epidermis
Serum Autoantibody Testing:
- test measures circulating autoantibodies against desmoglein 1 and 3
Tx of Pemphigus Vulgaris? [4]
First-Line Treatment
- oral corticosteroid ± azathioprine or mycophenolate
Second line:
- Rituximab
Intravenous immunoglobulin (IVIG) and plasmapheresis are adjunctive therapies for severe or refractory cases.
Patients on high-dose steroids or other immunosuppressants should receive prophylaxis against Pneumocystis jirovecii pneumonia with co-trimoxazole.
Notes: BMJ BP
Dx? [1]
Dermatitis Herpetiformis
Clinical features of dermatitis herpetformis? [5]
Symmetrical distribution
Scalp, shoulders, buttocks, elbows, knees
Very itchy papules and vesicles: scratching often leads to excoriation and crusting
onset of symptoms is variable and can occur at any age, although it is most common in the third to fifth decades of life
The disease course is characterized by periods of exacerbation and remission.
How do you dx dermatitis hepetiformis? [3]
Clinical presentation
Serology:
- Elevated levels of anti-tissue transglutaminase (tTG) antibodies or endomysial antibodies (EMA). Anti-deamidated gliadin peptide (DGP) antibodies may also be elevated.
Small intestinal biopsy
Histopathology:
- demonstrating subepidermal blisters with neutrophilic infiltrate
Response to diet:
- Improvement of symptoms upon adherence to a strict gluten-free diet is supportive but not solely diagnostic.
Tx for Dermatitis Herpetiformis? [2]
Gluten free diet for life
Dapsone
Dapsone can be used to treat dermatitis herpetiformis.
Name some side effects of using as treatment [2]
hemolytic anaemia and methemoglobinemia
- regular monitoring of complete blood counts and methemoglobin levels.
Patients with dermatitis herpetiformis have an increased risk of developing [], a rare but aggressive form of non-Hodgkin lymphoma.
Patients with dermatitis herpetiformis have an increased risk of developing Enteropathy-associated T-cell lymphoma (EATL), a rare but aggressive form of non-Hodgkin lymphoma.
Define erythroderma [1]
Name 5 causes
Widespread erythema of skin (over 90% of body surface area)
Causes
* Idiopathic (30%)
* Adverse drug reaction (gold)
* Known inflammatory skin disease (eczema, psoriasis)
* Cutaneous lymphoma
Dx? [1]
Describe the pattern seen here [1]
Eczema Herpeticum
* Monomorphic crusts / vesicles / papules
* History of eczema
Describe the clinical presentation of eczema herpticum [6]
The skin lesions of eczema herpeticum typically present as painful clusters of blisters, fluid-filled elevations of the skin
Areas of rapidly worsening, painful eczema
The blisters appear widely over the body but are most common on the face, neck, and trunk.
Older blisters that have burst and dried commonly form “punched out” erosions, which are circular breaks in the continuity of the skin that may bleed or produce pus.
Possible fever, lethargy, lymphadenopathy or distress
What is the name for when HSV can spread to the eye? [1]
What is the management? [1]
Rarely, HSV may spread to the eye resulting in herpes keratitis
Ganciclovir ointment five times daily (3 hourly) for 7-10 days
Describe what is meant by erythema multiforme
Erythema multiforme (EM) is a skin hypersensitivity reaction that commonly occurs secondary to an infection or drugs.* A hypersensitivity reaction is an exaggerated immune reaction that occurs in response to an antigen or allergen.*
What commonly causes erytherma multiforme? [3]
Describe the two types (EM minor/major) [2]
Causes:
Drugs or Infections (HSV, Mycoplasma)
EM Minor
– target lesions + mild/ no mucosal involvement
EM Major
– target lesions + 1 or more mucosal surfaces involved
Which areas are commonly affected by EM?
Symmetrical distribution on the extensor surfaces of acral extremities
Mucosal lesions commonly involve the oral mucosa and can lead to erythema, erosions, and/or bullae.
Describe the lesions in EM [3]
Where else can be commonly effected? [1]
EM is characterised by the presence of target lesions that are usually < 3 cm in size. These lesions have three striking features:
- A central blister or dusky red area
- A surrounding pale ring of oedema
- An erythematous halo in the periphery
It does not usually affect the mucous membranes but can cause a sore mouth (stomatitis).
A patient takes penicillin for an infection.
They come out in targetoid lesions.
What type of hypersensitivty reaction is this?
Type 1
Type 2
Type 3
Type 4
Type 1
Type 2
Type 3
Type 4
EM is considered a cell-mediated (type IV) hypersensitivity reaction, which is an abnormal cell-mediated reaction initiated by T cells.
The exact mechanism leading to EM is incompletely understood, but it appears to be an abnormal immune reaction to a drug metabolite or viral antigen that becomes expressed by keratinocytes within the skin
Dx? [1]
SJS
Describe in detail the skin lesions seen in SJS / TENs [4]
- Erythematous or purpuric macules
- Diffuse erythema
- Targetoid/ atypical target lesions
- Flaccid blisters
How do you dx SJS / TEN? [1]
What score is used for to classifiy the severity of SJS / TEN? [1]
Dx:
- skin biopsy
Severity:
- SCORTEN
sum of five points or more indicates a mortality risk of over 90%
Pathophysiology of staphylococcal scalded skin syndrome (SSSS)? [1]
staphylococcus aureus bacteria that produces epidermolytic toxins. These toxins are protease enzymes that break down the proteins that hold skin cells together
When a skin infection occurs and these toxins are produced, the skin is damaged and breaks down.
This condition usually affects children under 5 years. Older children and adults have usually developed immunity to the epidermolytic toxins.
Clinical presentation of SSSS? [5]
Fever:
- High fever (>38.9°C)
Rash:
- A diffuse, blanching erythroderma resembling sunburn usually appears early in the disease course.
- Desquamation, particularly on the palms and soles, typically occurs one to two weeks after the onset of illness
Myalgias and arthralgias are frequently reported;
Hypotension:
- Hypotension or shock may be present, often manifesting as systolic blood pressure less than 90 mmHg.
EM
Lichen planus
Lichen planus
Co-amoxiclav
