Lecture 3 Acute & Emergency Dermatology Flashcards
Consequence of mechanical barrier to infection
Sepsis
Consequence of failure of temperature regulation
Hypo-Hyperthermia
Consequence of failure of fluid and electrolyte balance
Protein and fluid loss
Renal impairment
Peripheral vasodilation
Causes of erythoderma
Psoriasis Eczema Drugs Cutaneous lymphoma hereditary disorders Unknown
Management of Erythroderma
- Remove any offending drugs
- Careful fluid balance
- Good nutrition
- Temperature regulation
- Emollients – 50:50 Liquid Paraffin : White Soft Paraffin
Mild drug reaction
Morbilliform exanthem
Macular rash, similar to measles
Severe drug reaction
Erythroderma, Stevens Johnson Syndrome/Toxic epidermal necrolysis, DRESS
Secondary causes of SJS
NSAIDs Antibiotics Anticonvulsants Allopurinol NSAIDs onset can be delayed
Clinical features of SJS
• Fever • Malaise • Arthralgia • Rash – Maculopapular, target lesions, blisters – Erosions covering <10% of skin surface • Mouth ulceration – Greyish white membrane – Haemorrhagic crusting • Ulceration of other mucous membranes • Painful • Dusky Skin sloughing • Lung involvement- CXR
Clinical Features of Toxic Epidermal Necrlysis
• Often presents with prodromal febrile illness
• Ulceration of mucous membranes
• Rash
– May start as macular, purpuric or blistering
– Rapidly becomes confluent
– Sloughing off of large areas of epidermis – ‘desquamation’ > 30% BSA
– Nikolsky’s sign may be positive- minor trauma removes epidermis
Management of severe drug reactions
- Identify and discontinue culprit drug
* Supportive therapy
How is the prognosis of severe drug reactions scored
SCORTEN criteria
What is SCORTEN criteria
– Age >40 – Malignancy – Heart rate >120 – Initial epidermal detachment >10% – Serum urea >10- dehydrated – Serum glucose >14- hyperglycaemic – Serum bicarbonate <20- highly acidic
SCORTEN 0-1
> 3.2% mortality
SCORTEN 2
> 12%
SCORTEN 3
> 35%
SCORTEN 4
> 58%
SCORTEN 5 or more
> 90%
Long term compilation of severe drug reactions
– Pigmentary skin changes – Scarring- genital sites – Eye disease and blindness – Nail and hair loss – Joint contractures- if scarring causes keloids
What causes erythema Multiforme
• Hypersensitivity reaction usually triggered by infection
– Most commonly HSV, then Mycoplasma pneumonia
Clinical features of Erythema Multiforme
• Abrupt onset of up to 100s of lesions over 24 hours
– Distal proximal
– Palms and soles
– Mucosal surfaces (EM major)
– Evolve over 72 hours
• Pink macules, become elevated and may blister in centre
• “Target” lesions
How is Erythema Multiforme managed
- Self limiting and resolves over 2 weeks
- Symptomatic and treat underlying cause
- More common in children and younger patients
Clinical features of DRESS
- Macules on skin
- Fever, lymphadenopathy, abnormal LFTs
- Eosinophilia
- DIC (Disseminated Intravascular Coagulation)
- Acute renal failure
Treatment of DRESS
- Stop causative drug
- Symptomatic and supportive
- Systemic steroids
- +/- Immunosuppression or immunoglobulins
Clinical features of Pemphigus
Uncommon Not acute Middle aged patients Blisters very fragile- no intact Mucous membrane affected Patients unwell
How is Pemphigus treated
Systemic steroids
Dress erosions
Supportive therapies
Cause of Pemphigus
Antibodies targeted against desmosomes
Split epidermis = blister
How is Pemphigus diagnosed
• Immunofluorescence- key test to diagnose- process it with antibodies IgG = strongly positive
Histology
Clinical features of Pemphigoid
Common
Elderly patients
Blisters often intact and tense
Patients fairly well systemically
How is pemphigoid treated
Topical steroids
What are the common causes of Erythrodermic psoriasis and Pustular Psoriasis
– Infection
– Sudden withdrawal of oral steroids or potent topical steroid
Clinical features of Erythrodermic psoriasis and Pustular Psoriasis
Fever
Elevated WBC
• Rapid development of generalised erythema, +/- clusters of pustules
Treatment of Erythrodermic psoriasis and Pustular Psoriasis
- Exclude underlying infection, bland emollient, avoid steroids
- Often require initiation of systemic therapy
What is Eczema Herpeticum
• Disseminated herpes virus infection on a background of poorly controlled eczema
What are the clinical features of Eczema Herpeticum
• Monomorphic blisters and “punched out” erosions
– Generally painful, not itchy
• Fever and lethargy
Elevated WCC
Treatment of Eczema herpeticum
Aciclovir
Mild topical steroid to treat eczema
What is Staphylococcal Scaled Skin Syndrome
Diffuse erythematous rash with skin tenderness
What is the cause of Staphylococcal Scaled Skin Syndrome
Staph infection
Clinical features of Staphylococcal Scaled Skin Syndrome
• More prominent in flexures
• Blistering and desquamation follows
– Staphylococcus produces toxin which targets Desmoglein 1 (desmosal protein)
• Fever and irritability
Treatment for Staphylococcal Scaled Skin Syndrome
IV antibiotics
resolves 5-7 days
What is acute urticaria
<6 week history
usually Viral or Idiopathic
What is the treatment for acute urticaria
Oral anti-histamine
4 doses
What is chronic urticaria
> 6 week history
Autoimmune/idiopathic
What is the treatment for Chronic urticaria
- Non sedating H1 antihistamine
- Higher dose up to four times
- Consider 2nd line agent anti-leukotriene or angiodema
- Immunomodulant- omalizumab, cyclosporine
