Dermatological Emergencies Flashcards
What are the different types of skin drug reactions?
Maculopapular,
Urticaria,
Morbilliform (blanching, erythematous rash)
Papulosquamous,
Photo-toxic,
Pustular,
Lichenoid rash (looks similar to lichen planus),
Psoriasiform rash (sudden onset, common drugs include lithium and beta blockers)
What are some common drugs which can cause acute drug reactions?
Antibiotics eg, penecillin and trimethoprim,
NSAIDs,
Allopurinol
Chemotherapeutic agents,
Psychotropic (chlorpromazine),
Anti-epileptic,
Cardiac drugs,
OCP.
The A’s - Anticonvulsants, antibiotics, anti-inflammatories, allopurinol
What is a fixed drug rash?
It is a reaction which occurs in the same place everytime you take the same drug
What are some blistering disorders induced by drugs?
Steven Jonson syndrome (blistering and bleeding around mucous membranes) and toxic epidermal necrolysis
What are the features of steven-johnson syndrome?
Maculopapular rash with target lesions which may develop into vesicles.
Positive Nikolsky sign - blisters/erosions appear when skin is rubbed gently
Mucosal involvement
Systemic symptoms (fever and arthralgia)
Management - hospital admission for supportive
WHat does the following image show and what are its features?
Shows: Toxic epidermal necrolysis
Presentation: Systemically unwell (pyrexial, tachycardia) and positive nikolsky sign
What are some drugs known to induce TEN?
- Phenytoin,
- Sulphonamides,
- Allopurinol,
- Penicillins,
- Carbamazepine,
- NSAID
How are SJS and TEN classified?
SJS is when <10% of body surface is involved.
SJS/TEN overlap is when 10-30% of body surface is involved.
TEN is when > 30% of the body surface is involved.
What are the investigations for SJS/TEN?
- Skin biopsy - for definitive diagnosis
- Blood cultures - rule out TTS amd scalded skin syndrome
- FBC - Look for eosinophils for DRESS.
- U&Es, LFTs, CRP, ABG.
- Mycoplasma serology - mycoplasma infection can cause SJS/TEN
What infections can cause SJS?
- Upper resp tract infections,
- Mycoplasma pneumoniae,
- Herpes,
- EBV,
- CMV,
- Pharyngitis
- Otitis media
What are risk factors for SJS/TEN?
- Active cancer,
- Anticonvulsant meds,
- Recent infection,
- Recent abx use,
- SLE,
- HIV positive,
- Radiotherapy,
- Human leukocyte antigen and family history (may need to do HLA testing prior to some anticonvulsants)
- Smallpox vaccine
What is the management for TEN?
- Stop precipitating drug.
- Give IV immunoglobulin
- Manage in HDU with fluids and monitor electrolytes.
What is DRESS and management?
Drug Reaction with Eosinophilia and Systemic Symptoms. It is a delayed type IV hypersensitivity reaction. Managed with Oral prednisolone
What is the presentation of DRESS?
Morbilliform rash with systemic symptoms eg, fever, multi-organ dysfunction, haem abdnormalities, neuro/endocrine/GI abnormalities and raised eosinophils
Characteristic finding = facial oedema
What is the following image and its causes?
- Erythema multiforme minor. Hypersensitivity reaction which can be caused by:
- Herpes simplex virus,
- Idiopathic
- Mycoplasma or streptococcus,
- Drugs(rare) - Penicillin, sulphonamides, carbamazepines, allopurinol, NSAIDs, OCP,
- Connective tissue disease - SLE<
- Sarcoidosis,
- Malignancy
What is erythema multiforme major?
It is when there is also mucosal involvement. More commonly drug induced.
What is the management of erythema multiforme?
Treat underlying cause and then it usually resolves on its own.
EM minor - topical emolient and topical steroid.
EM major - Topical emolient and oral/IV steroids
If recurrent then use aciclovir, dapsone or azathioprine
What does the following image show
Urticaria. It is a pruritic pale, blanching swelling which lasts up to 24h.
Acute - less than 6weeks
Chronic - Longer than 6 weeks
What are the different types of urticaria?
Immune mediated - Type 1 IgE response.
Non-immune mediated - diresct mast cell degranulation which can be caused by opiates, abx, contrast media or NSAIDs.
What are some causes of acute urticaria?
Many are unknown but can be caused by:
- Viral infections,
- Medications,
- Food and food additives,
- Parasitic infections,
- Physical stimulants (cold, chlorine)
What is the treatment of urticaria?
1st line = non-sedating antihistamines eg, cetirizine for 6 weeks.
Sedating antihistamine if struggling with sleep (chlorphenamine)
Steroids if severe or recurrent episodes
2nd line = LTRA or omalizumab. Can give sterids if severe
What is eryhtroderma?
Erythema covering more than 90% of the body’s surface
What are some of the causes of erythroderma?
Psoriasis,
Eczema,
Pityriasis rubra pilaris,
Drug allergies,
Idiopathic,
Sezary syndrome: cutaneous T cell Lymphoma
What are the investigations for erythroderma?
FBC and CRP,
Skin biopsy.
