Emergency Dermatology Flashcards
What is erythema nodosum? What can cause it?
A hypersensitivity response to a variety of stimuli
Infective:
- Group A beta-haemolytic streptococcus (Strep pyogenes)
- Primary tuberculosis
- Chlamydia
- Leprosy
Inflammatory:
- IBD
- Sarcoidosis
- Behçet’s disease (mouth sores, genital sores, ant/post uveitis, arthritis, IBD Sx, haemopytsis, pericarditis)
Cancer incl. NHL
Pregnancy
Drugs: COCP, sulfa and penicillin drugs
How does erythema nodosum present?
Discrete tender nodules which may become confluent
Lesions continue to appear for 1-2 weeks and leave bruise-like
discolouration as they resolve
Lesions do not ulcerate and resolve without atrophy or scarring
The shins are the most common site
How do we manage erythema nodosum?
We need to look for an underlying cause
What is erythema multiforme?
Often of unknown cause, is an acute self-limiting inflammatory condition with herpes simplex virus being the main precipitating factor
Other infections and drugs are also causes
Mucosal involvement is absent or limited to only ONE mucosal surface
Target lesions
What is Stephen-Johnson Syndrome?
Mucocutaneous necrosis with at least two mucosal sites involved
Skin involvement may be limited or extensive
Drugs or combinations of infections or drugs are the main associations
Epithelial necrosis with few inflammatory cells is seen on
histopathology
The extensive necrosis distinguishes Stevens-Johnson syndrome from erythema multiforme
May have features overlapping with toxic epidermal necrolysis including a prodromal illness
What is toxic epidermal necrolysis?
Usually drug-induced, is an acute severe similar disease characterised by extensive skin and mucosal necrosis accompanied by systemic toxicity
On histopathology there is full thickness epidermal necrosis with subepidermal detachment
How do you manage erythema multiforme, SJS and TEN?
Call for help
Fluids/supportive care to maintain haemodynamic equilibrium
Mortality rates are high due to sepsis, electrolyte imbalance or multi-system organ failure
What is acute meningococcaemia?
A serious communicable infection transmitted via respiratory
secretions; bacteria get into the circulating blood
Caused by N. meningitides = G-ve diplococcus
How does acute meningococcaemia present and how is it managed?
Features of meningitis (e.g. headache, fever, neck stiffness),
septicaemia (e.g. hypotension, fever, myalgia) and a typical rash
- Non-blanching purpuric rash on the trunk and extremities, which
may be preceded by a blanching maculopapular rash, and can
rapidly progress to ecchymoses, haemorrhagic bullae and tissue necrosis
Management:
- Antibiotics (e.g. benzylpenicillin)
- Prophylactic antibiotics (e.g. rifampicin) for close contacts (ideally within 14 days of exposure)
What is erythroderma?
Exfoliative dermatitis involving at least 90% of the skin surface
What causes erythroderma?
Previous skin disease (e.g. eczema, psoriasis), lymphoma, drugs
(e. g.sulphonamides, gold, sulphonylureas, penicillin, allopurinol,
captopril) and idiopathic
How does erythroderma present?
Skin appears inflamed, oedematous and scaly
Systemically unwell with lymphadenopathy and malaise
May deteriorate:
- Secondary infection (as weak defence)
- Fluid loss and electrolyte imbalance
- Capillary leakage
How do you treat erythroderma?
Treat the underlying cause, where known
Emollients and wet-wraps to maintain skin moisture
Topical steroids may help to relieve inflammation
What is eczema herpeticum?
Widespread eruption - serious complication of atopic eczema or
less commonly other skin conditions
Caused by herpes simplex virus
How does eczema herpeticum present?
Extensive crusted papules, blisters and erosions
Systemically unwell with fever and malaise
Secondary infection with Staph or strep may lead to impetigo or cellulitis
