SSS Week 6

Dermatological Emergencies

Steven Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TENS) Presentation, characteristics, complications, management

Presentation

1. 1-3 days of prodromal sore throat, fever malaise and conjunctivitis

2. followed by skin blistering and skin loss in sheets leaving painful raw areas

characteristics

• characterised by necrosis and detachment of epidermis

• erosions of mucosal surfaces including conjunctiva, oropharynx, oesophagus, urethra and vagina

• SJS tends to be on the trunk and face but TENS is generalised (TENS can have multi-organ failure)

• almost always drug related (antibiotics, anticonvulsants etc) and there are also HLA associations in some races to anticonvulsants and allopurinol

common agents

• Co-trimazole

• Lamotrigine

• carbamazepine

• phenytoin

• allopurinol

• piroxicam and meloxicam (NSAID)

Systemic involvement

• hepatitis

• pancytopenia

• DIC

• acute resp distress syndrome

• GIT bleeding

• sepsis

Complications

Severe ocular complications, pigment alteration, sicca syndrome,

scarring to mucosal surfaces and vagina and esophageal stricture

Management

 Cease all suspected drugs

 ICU / burns unit

Erythema Multiforme characteristics, aetiology, diagnosis, management

• Characterised by classic targetoid lesions, raised, round papule with a darker, blistered centre surrounded by a pale oedematous ring with a red edge in crops DOES NOT MIGRATE (Unless urticaria which is Ddx)

  

• affects only skin and mucous membranes

• most common cause is HSV infection

TWO TYPES: EM minor, EM major

EM minor: usually result of HSV and occasionally drugs

EM major: usually HSV and Mycoplasma pneumonia

EM minor is limited to the skin and mainly on the extremities whereas major is where mucosal membranes are also affected, and large areas of skin are involved

Dx : skin biopsy with histology

Management

• treat underlying cause

• symptomatic relief

  EM major can cause significant morbidity but not life threatening, usually lasts 2 weeks

DRESS (drug reaction with eosinophilia and systemic symptoms) what is it, what drugs, management

DRESS is a severe, potentially fatal, drug hypersensitivity reaction characterized by a high fever, malaise, facial oedema and generalised morbilliform rash which can progress to erythroderma, eosinophilia (high eosinophil counts), and can have additional symptoms such as (lymphadenopathy, hepatitis, nephritis, pneumonitis, myocarditis) that typically develops 2–6 weeks after starting a new medication

What drugs are involved

• anticonvulsants

• antibiotics including minocycline

• allopurinol

• terbinafine

• antiretrovirals

• azathioprine

• dapsone

Management

• oral steroids

Type I anaphylactic reactions (aetiology, ddx, management)

Anaphylaxis, urticaria, angioedema

Urticaria

classical lesion is a wheal which indicates dermal oedema (erythematous raised lesion, annular or polycyclic or targetoid)

• due to histamine release

• does not involve the epidermis so no scale, blistering or disruption of skin, only involves dermis

• in very young children, urticaria may appear purple and may be followed by bruising cus of vessel fragility

Aetiology

• food allergens

• insect toxins

• inhaled substances

• medications

• ACE Inhibitors

• blood products

• IV contrast

• viral infectiosn, occasionally worms

physical urticaria can also be induced from cold, sweating, water, vibration and pressure, scratching skin (dermographism - a common form of physical urticaria, occurs when skin is stroked or scratched)

Ddx (urticaria is the only one that migrates)

• erythema nodosum

• cellulitis

• drug reactions

Management of acute vs chronic urticaria

Acute

• withdraw the cause if found

• antihistamines (H1) less sedating (loratadine) vs sedating (promethazine)

• if response to antihistamines 1 is poor then use a H2 histamine eg. ranitidine

• NO STEROIDS cus its pureply histamine reaction

Chronic >6-12 weeks

• specific cause unlikely to be found

• investigations TFT, RAST, FBC, hepatitis serology, analogous serum skin testing,

• treatment includes trial elimination diet

• avoid NSAIDs and aspirin

• antihistamines and if that fails immunosuppressants (regular IV injections)

Angioedema

• involves deeper tissues compared to urticaria, presents with areas of skin coloured swelling (usually face, eyelids, hands and feet) and can obstruct airway

Anaphylaxis

• Anaphylaxis is a life-threatening emergency caused by massive release of histamine

• first sign is often dizziness and skin itching and burning

• may have wheezing, feelings of panic and anxiety, and gi involvement (vomiting and abdo pain)

• frequently an urticarial rash, and angioedema of face, neck and airway

• patients may progress rapidly to circulatory collapse leading to hypotension and shock

• laryngeal oedema and bronchospasm lead to respiratory arrest

Management

• ABC

• any suspect drug should be ceased immediately

• administer oxygen 6-8+ L/minute

• adminster adrenaline IM, may be repeated every 5 minutes and may be given IV

• lay patient flat and elevate legs, monitor vitals and ecg

• if hypotensive, rapid IV replacement

• if there is severe laryngospasm, bronchospasm, shock or patient is unconscious, u must intubate and commence positive pressure ventilation and call MET

• stridor: nebulised adrenlaline, intubation if needed

• wheeze: salbutamol or adrenaline by nebuliser

• monitor for at least 4-6 hours for biphasic reaction

• later… organise epipen for patient, medical alert bracelet and establish anaphylaxis action plan

SOFAH

just remember for adults, 0.25, 0.5, 0.75 and for kids divide by 10

Erythema

used to describe any skin disease that involves 90% or more of the body surface area

• can be inflammatory , erythematous or scaly

loss of skin barrier can cause systemic disturbance. like hypothermia, fluid and protein loss, electrolyte disturbance and cardiac failure

FIVE MAIN CAUSES

1. dermatitis

2. psoriasis

3. cutaneous lymphoma

4. drug reactions (DRESS)

5. pityriasis rubra pilaris (very rare)

Types of cutaneous drug reactions

Vasculitis (type 3 immune complex mediated) - characteristics, aetiology

vasculitis - inflammation of blood vessels
(size of blood vessels affected determine the clinical appearance of the rash)

superficial:

• palpable purpura, ulcers and necrosis, no blanch, most likely found in areas where immune complexes settle due to gravity (so lower legs or for bed bound patients, the back, buttocks and legs)

• histopathology is damage to vessel walls by PMN leukocytes

examples

1. acute meningococcaemia (spread by resp droplets, neisseria meningococcus (fever, severe headache, photophobia, neck stiffness, myalgia and arthralgia)

2. IgA medicated vasculitis : Henoch-Schlonlein purpura (in kids, rarely in adults, palpable purpura associaed with arthritis, abdo pain and nephritis)

3. acute haemorrhagic oedema (in babies and toddlers, probably viral)

4. urticarial vasculitis (persistent urticarial-like wheals but does not migrate, leaves bruising and hyperpigmentation)

Medium sized vessel vasculitis

• most common is polyarteritis nodosa

• presents with nodules, livedo reticularis and ulcers

• systemic disease is common, affecting joints, peripheral nerves, muscles, myocardium and kidneys

Mixed (small and medium vessels involved)

• most common is granulmatosis with polyangiitis

• presents with severe necrotising and ulcerating skin lesions, with involvement of upper and lower respiratory tract and kidneys

deeper and larger: nodules and plaques

other presentations include urticarial lesions, bruises, blisters, livedo reticularis, vesicles and pustules

also a HALLMARK of meningococcal infection

aetiology

• 50% is idiopathic

• iral and bacterial infection, particularly meningococcal disease but accompanying any form of sepsis (meningococcus, strep, hep b and c, hiv)

• underlying connective tissue disease - SLE and rheumatoid arthritis (immune complex)

• hypersensitivity reaction to drugs (immune complex)

in chiildren 3 main causes KNOW THEM

• infection most often strep

• henoch schlonlein purpura, a characteristic IgA mediated vasculitis

• acute haemorrhagic oedema

Management

• uncomplicated small vessel vasculitis is usually benign, and self-limiting, resolved once underlying trigger removed

• examine for systemic disease signs like hepatosplenomegaly, lymphadenopathy, ocular involvement, CNS abnormalities and joint swelling

• urinalysis

• skin biopsy with immunofluorescence for IgA

• FBC

• ESR

• U&E

• LFT

• ASOT?

• for larger vessels ANCA - detects anti-neutrophil antibodies

• possible connective tissue screening if SLE is suspected

Toxic shock syndrome clin features

multisystem disease resulting from exotoxin from S.aureus or S.pyogenes

• varicella may precede strep toxic shock, associated with retained tampon

clin features

• fever

• malaise

• headache

• pharyngitis

• myalgia

• erythematous macular or scarlatiniform rash most obvious in the flexures and on hands and feet

• oedematous face, hands and feet too

• enanthem (rash of mucous membrane) with reddened lips and tongue and mild conjunctivitis

• multiorgan involvement can occu

• otne leukocytosis and raised LFTs

• platelet count may be low and DIC can occur

• usually desquamation 2-3 weeks after rash

• hair loss and nail dystrophy may occur

Kawasaki disease

multisystem vasculitis with cutaneous, mucosal and systemic manifestations

• affects kids aged <5

• The most sinister association of this condition is coronary artery lesions in about 20% of cases. If left untreated this can lead to aneurysm, thrombosis, myocardial infarction and death.

no known cause, no specific diagnostic test, blood tests aren’t diagnostic. there is commonly leukocytosis, thrombocytosis and raised ESR and CRP

SSSS clin features

caused by exotoxins of S.aureus

like kawasaki disease children aged <5

clin features

• fever, macular erythema (like superficial burn) and then superficial blistering

treatment

• early oral antibiotics

• late IV and hospital

Patient with multiple blisters and pustules causes

majority of conditions are not life-threatening (except SJS, TENS, and EM)

causes can be

1. infection (varicella zoster, HSV (eczema herpeticum), staph. folliculitis, bullous impetigo, SSSS, bacterial:necrotising fasciitis)

2. allergic reactions (contact dermatitis, allergen contact w skin, type iv reaction, drug reactions (doxy (photoallergic reactions) AGEP, TENS), rash is usually erythematous, oedematous)

3. pustular psoriasis, rare erythroderma with tiny sterile pustules, need to exclude infection and needs hospital admission)

4. immunobullous diseases rare, bullous pemphigoid

5. pompholyx (dyshidrotic dermatitis)

Eczema Herpeticum (definition, clin features, complications, management)

• Definition:
  Eczema herpeticum is a disseminated viral infection characterised by fever and clusters of itchy blisters or punched-out erosions. It is most often seen as a complication of atopic dermatitis/eczema.

• Clinical Features:

  • Extensive crusted papules, blisters, and erosions

  • Primary HSV infection presents with fever and malaise

• Complications:

  • Systemic dissemination of herpes with hepatitis, encephalitis, DIC, and death in immunocompromised patients

• Management:

  • Treat underlying atopic eczema

  • Antivirals

Necrotising Fasciitis (definition, aetiology, risk factors, clin features, complication)

• Definition:
  Infection of deep fascial planes leading to necrosis of subcutaneous tissue and skin.

• Etiology:

  • Usually Group A Streptococcus

• Epidemiology / Risk Factors:

  • 50% occur in healthy individuals

  • Risk factors: skin trauma, abdominal surgery, diabetes, immunosuppression

• Clinical Features:

  • Severe pain in affected area

  • Oedema, foul-smelling exudate

  • Skin blistering, necrosis

  • Patient is systemically unwell

• Complications:

  • Streptococcal toxic shock may occur

Management of drug eruptions

• identify causative drug

• investigations (no diagnostic test, eosinophilia and raised LFTs often occur - skin biopsy may be helpful but not diagnostic)

• stop suspected drug and replace with chemically unrelated drug (may continue under certain circumstances but seek advice first - is essential, no substitute, used for short time, no urticaria or skin blistering, anaphylaxis or severe reactions)

• further management: most reactions cease within 1-2 weeks EMOLIENTS AND STEROID CREAMS (MAINSTAY), antihistamines for urticarial drug reactions, oral steroids for 1-2 weeks for very itchy and uncomfortable exanthematous

Management of Severe Drug reactions

• requires dermatological opinion in hospital

• needs FBC, LFT, urinalysis and skin biopsy

• ophthalmology opinion if conjunctivitis

• mycoplasma serology, CXR and viral swabs on admission

• management: as discussed for DRESS and erythema multiforme and TENS (cease drug, oral steroids?, burns unit for TENS?)

• prevention: emergency bracelets, first degree relatives at risk so take precautions

Different types of cutaneous drug reactions

things to remember:

• Any widespread rash occurring within 2-3 weeks of commencing

  a new drug should be suspected of being due to the drug.

• it is necessary to sort them

  into those that have been most recently commenced and are

  temporally related to the onset of the rash

• There is no one diagnostic tests however an eosinophilia and

  raised LFT's often accompany drug reactions. Skin biopsy may be

  helpful

• If a patient has been able to tolerate a drug several times in the past without a reaction, it is also very unlikely for them to suddenly become allergic to it.

• Antihistamines will only be effective for urticarial drug reactions. There is no value

  in administering them for any other type of drug reaction.

Types of drug reactions (in simplified table form)

Type	Key Features	Onset	Common Drugs	Notes
Exanthematous	Diffuse red maculopapular rash	2–3 weeks	Antibiotics, anticonvulsants	Most common
Urticarial	Hives, itching	24–36 hrs	Penicillins, NSAIDs, ACEi	May progress to anaphylaxis
Vasculitic	Purpura (esp. legs)	Variable	Aspirin, cytotoxics	Rule out infection
Phototoxic	Sunburn-like rash	Days	Tetracyclines, amiodarone	Sun-exposed areas only
Pustular (AGEP)	Small pustules, fever	≤2 weeks	Antibiotics, terbinafine	Looks like pustular psoriasis
Eczematous/Lichenoid	Chronic eczema-like	Variable	Thiazides, gold	Rare
Fixed drug eruption	Recurs in same spot	Hours–days	Sulfonamides, NSAIDs	Heals with pigmentation