Dermatological Emergencies Flashcards
What is erythroderma?
widespread inflammation affecting 90% or more of the body surface
What are the symptoms of erythroderma?
Thirst Fever Chills Malaise Diziness
Generalised lymphadenopathy can occur in erythroderma?
Yes - especially in erythroderma caused by underlying malignancy
List some common causes of erythroderma?
Atopic eczema Psoriasis Drugs - sulphonamides, gold, sulphonylureas, penicillins Seborrhoeic eczema Idiopathic
List some rare causes of erythroderma?
Chronic actinic dermatitis Cutaneous T cell lymphoma Malignancy - especially leukaemia Pemphigus foliceus Pityriasis rubra pilaris HIV infection Toxic shock syndrome
What are the complications of erythroderma?
High output cardiac due to increased blood flow
Hypothermia from heat loss
Pre-renal acute kidney injury due to fluid depletion
Hypoalbuminaemia
Catabolism
Secondary bacterial infection
Capillary leak syndrome
Describe capillary leak syndrome
Here the release of inflammatory mediators from the skin causes extensive vascular leakage which can lead to oedema, hypovolaemic shock and acute respiratory distress syndrome
Describe the management of erythroderma?
Supportive treatment - maintain body temperature (space blankets, heaters) and close monitoring
Skin swabs if secondary infection suspected
Stop non-essential medication
Topical therapy with bland emollient or mild topical steroids while underlying cause is identified
Treat underlying cause
What are the different types of skin drug reactions?
Maculopapular rash Urticaria Papulosquamous rash Phototoxic rash Pustular rash Lichenoid rash Fixed drug rash Bullous rash Itch
List some common drugs which cause acute rashes
Antibiotics - penicillins, trimethoprim NSAIDs Chemotherapeutic agents Psychotropic agents Anti-epletic agents Cardiac drugs - beta blockers, ACE inhibitors, anticoagulants
Where do maculopapular drug rashes usually occur?
On the torso and spread to the face and limbs but spare the mucosae
Maculopapular drugs rashes are self limiting and usually clear within how many weeks?
1-2 weeks
What conditions are classed as severe drug rashes?
Stevens Johnson syndrome and toxic epidermal necrolysis
Drug reaction with eosinophilia and systemic symptoms
Acute generalised exanthematous pustulosis
Serum sickness like reactions
What drugs are common causes of severe cutaneous drug reactions?
Antibiotics NSAIDs Anticonvulsants Allopurinol Dapsone Nevirapine
Define Steven johnson syndrome
A severe mucutaneous disorder characterised by blistering, epidermal detachment and mucosal ulceration
SJS occurs when there is <10% skin detachment and one/two mucosal sites involved
What is Steven Johnson syndrome and toxic epidermal necrolysis overlap syndrome?
When there is 10-30% skin detachment
At what point does disease progress to toxic epidermal necrolysis?
when there is >30% skin detachment and all mucosal sites are involved
Describe the pathophysiology of Steven Johnson syndrome and toxic epidermal necrolysis?
Cytotoxic T cells attack epithelial cells in the mucosa and epidermis in response to a drug antigen and release perforin (which lysis target epithelial cells) and granzymes (which induces necrosis of epithelial cells). T cells are release pro-inflammatory cytokines which attract other immune cells
This leads to a loss of skin barrier protection, erosion of the affected skin and mucosa and detachment at the basement membrane
Which medications most commonly cause Steven Johnson syndrome and toxic epidermal necrolysis?
Antoconvulsants
Antibiotics
NSAIDs
Other than drugs, what. can cause Steven Johnson syndrome and toxic epidermal necrolysis?
Mycoplasma pneumonias infection
Cytomegalovirus infection
How long after drug exposure does Stevens Johnson syndrome / toxic epidermal necrolysis usually occur?
1-2 weeks
What are the symptoms fo Steven Johnson syndrome / toxic epidermal necrolysis?
Initial non-specific symptoms of malaise, myalgia, fever and cough
Formation of tender maculopapular lesions on the torso and mucosal surfaces
What scoring system can be used to estimate prognosis in Steven Johnson syndrome / toxic epidermal necrolysis?
SCORTEN
How is Steven Johnson syndrome / toxic epidermal necrolysis managed?
High dose steroids
Ciclosporin
IV immunoglobulin therapy
Stop possible causative. drugs
How many weeks after drug exposure does drug reaction with eosinophilia and systemic symptoms usually occur?
2-6 weeks
Describe the presentation of drug reaction with eosinophilia and systemic symptoms?
Widespread erythema, facial oedema, fever, lymphadenopathy and hepatosplenomegaly
What drugs are a common cause of drug reaction with eosinophilia and systemic symptoms?
Anticonvulsants
How is drug reaction with eosinophilia and systemic symptoms managed?
Systemic steroids
Where does the small, non-follicular sterile pustules usually form in acute generalised exanthematous pustulosis?
Neck
Axillae
Groin
How is acute generalised exanthematous pustulosis treated?
Topical steroids and emollients
What is erythema multiforme?
A self-limiting, symmetrical rash characterised by target lesions on the distal limbs, palms and soles
Describe the characteristic appearance of the rash in erythema multiforme?
Concentric rings of erythema with a dusky centre, which may occasional blister
Vesicles and papule may be present
Erythema multiforme can affect mucous membranes. T/F?
True - but only in erythema multiforme major
What type of hypersensitivity reaction is erythema multiforme?
Type IV hypersensitivity reaction
What is the most common trigger for erythema multiforme?
Herpes simplex virus
Describe the management of erythema multiforme?
Supportive with analgesia and fluids (possibly IV)
What is immunobullous disease?
An autoimmune disease which targets antigens in keratinocytes and the basement membrane to cause skin blistering
What investigations can be used for immunobullous disease?
Light and electron microscopy
Immunofluorescence
Describe the difference between direct and indirect immunofluorescence testing for immunobullous disease?
Direct - investigates the presence of antibody deposition in affected skin
Indirect - investigates the presence of circulating skin autoantibodies
In which ethnic groups is pemphigus vulgaris most common?
Ashkenazi Jews
People from the Indian subcontinent
Describe the pathophysiology of pemphigus vulgaris?
IgG4 antibodies attack desmosomal proteins causes a loss of keratinocyte adhesion in the skin and mucous membranes
Where does the rash commonly occur in the pemphigus vulgaris?
Torso
Where does the rash commonly occur in the pemphigus foliaceus?
Seborrhoeic areas e.g. scalp, face and upper chest
How is pemphigus vulgaris and pemphigus foliaceus treated?
High dose systemic corticosteroids
Immunosuppressants e.g. azathioprine, cyclophosphamide, methotrexate, ciclosporin
What age group is most commonly affected by bullous pemphigoid?
Patients >60 years
Describe the pathophsyiology of bullous pemphigoid?
There are large, tense, serous or haemorrhage blisters (bullae) which can appear anywhere on the body but especially on the limbs and torso
Pemphigoid can be very itchy. T/F?
True
How is bullous pemphigoid treated?
Oral corticosteroids
Long term steroid sparing agents e.g. azathioprine, mycophenolate mofetil
Topical steroid
