paeds derm Flashcards
what is stevens johnson syndrome
a severe systemic reaction affecting the skin and mucosa that is almost always caused by drug reactions
Defined as severe skin detachment with mucocutaneous complications
Aetiology of stevens johnson syndrome
infection: URTI, pharyngitis, otitis media, herpes
Vaccinations: small pox
Medications:
- anticonvulsants
- antibiotics
- antifungals
- NSAIDs
- penicillin
- allopurinol
- oral contraceptive pill
- sulphonamides
patients with what disease are at an increased risk of SJS
patients with HIV and active cancer
pathophysiology of stevens johnson syndrome
immune reaction to foreign antigens- immune complex mediated
what can stevens johnson develop into ?
toxic epidermal necrolysis
How does stevens johnson syndrome present?
rash- maculopapular with target lesions, can develop into vesicles and bullae
Nikolsky’s sign- the epidermal layer sloughs easily off when pressure is applied
erosions and ulcerations of eyes, lips, mouth, pharynx, oesophagus, GI tract
Systemic symptoms- fever, arthralgia
differentials for stevens johnsons syndrome
staphyloccocal scalded skin
toxic shock syndrome
erythema multiforme
burns
What is the definitive test for stevens johnsons syndrome
skin biopsy - shows keratinocyte apoptosis with detachment of the epidermal layer of the skin from the dermal layer
1st line management of stevens johnsons syndrome
hospital admission and removal of the causative agent
treatment of stevens johnson syndrome
- hospital admission and removal of the causative agent
- VTE prophylaxis
- surgical wound care
- analgesia
- fluid and electrolyte management
- nutritional support
- PPI
May consider IV immunoglobulins
what percent of the skin is involved in stevens johnson syndrome
less than 10%
what percent of the skin is involved in toxic epidermal necrolitis
at least 30%
mortality rate of stevens johnsons syndrome
10%
what can cause mortality in stevens johnsons syndrome (3)
dehydration
infection
disseminated intravascular coagulation
What are strawberry naevi and when do they present?
a type of birth mark, also called cavernous haemangioma
They present a few weeks after birth and usually regress over few years
How can strawberry naevi be treated?
topical propranolol- if severe and affecting vision or airways may use oral propranolol
What is a mongolian blue spot
a blue/black discolouration at the base of the spine and buttocks - it is a type of birth mark that usually fades over the first few years and can be commonly mistaken for bruises
What is a port-wine stains
a birth mark present from birth that is due to vascular malformation of the capillareis in the dermis
associations of port wine stains
if along the trigeminal nerve they may be associated with intracranial vascular abnormalities (Sturge -weber syndrome) or severe lesions on the limbs with bone hypertrophy (Klippel trenuay sydnrome
what may be used to reduce the appearance of port wine stains
lase therapy
Causes of eczema exacerbations (6)
bacterial or viral infections
ingestion of irritants
contact with irritants or allergens
environmental factors - heat, humidity,
change in medication
psychological stress
Describe eczema
itchy erythematous rash
in infants it commonly affects the face and scalp
in older children it is common in the skin flexures and frictional areas (neck, wrists)
How is eczema managed
- avoidance of irritants
- emollients
- topical steroids
- wet wrapping
Give some examples of mild, moderate and potent steroids
mild- 1% hydrocortisone
moderate- clobetasone butyrate (0.5%)
potent- betamethasone valerate (0.1%)
what types of medicaations might be used in very severe eczema
oral steroids
immunmodulators- calcineurin inhibitors
light therapy
DMARDS and biologics
What can occur if someone with eczema gets infected with HSV
eczema herpeticum
How does eczema herpeticum present ?
vesicles and punched out erosions appear at many sites on the body
how is eczema herpeticum diagnosed?
swab and Tzanck test
How is eczema herpeticum treated
IV aciclovir (often given with antibiotics as hard to differentiate)
what is allergic rhinitis
inflammation of the internal nose caused by an allergen
What type of reaction is allergic rhinitis
type 1 hypersensitivity (IgE mediated)
What three subtypes of allergic rhinitis are there?
seasonal (hayfever)
perennial
occupation
How does allergic rhinitis present?
sneezing
bilateral nasal obstruction
clear nasal discharge
post nasal drip
nasal pruritis
itchy swollen eyes
How is allergic rhinitis treated?
avoidance of the allergen
mild- intranasal or oral antihistamines
moderate - severe- intranasal corticosteroids
What should be avoided in chronic allergic rhinitis
topical nasal decongestants - can cause rebound hypertrophy of the nasal mucosa on withdrawal
(rhinitis medicamentosa)
How does eczema locations differ with age?
infants- face and trunk
young children- extensor surfaces
older children- flexor surfaces, neck
