derm Flashcards
SJS vs TEN: which is more extensive?
TEN>SJS
- 30% vs <10% mortalitty
SJS and TEN are
severe mucocutaneous reactions, usually to drugs, characterised by blistering and epithelial sloughing
- widespread epithelial keratinocyte apoptosis and necrosis, initiated by drug-induced cytotoxic T-lymphocytes
how do we categorise SJS and TEN cases?
- SJS: epidermal detachment<10% BSA, with widespread purpuric macules or flat atypical targets
- Overlap SJS-TEN: detachment of 10-30% BSA, with widespread purpuric macules or flat atypical targets
- TEN with spots: detachment >30% BSA, with widespread purpuric macules or flat atypical targets
- TEN without spots: detachment: >30% BSA, with loss of large epidermal sheets without purpuric macules or target lesions
most common drugs causing sjs/ten
- allopurinol
- lamotrigine
- sulfamethoxazole
- carbamazepine
- phenytoin
- nepvirapine
- sulfasalazine
- other sulfonamides
- oxicam NSAIDs: piroxicam, tenoxicam
- phenobarbital
- etoricoxib
likely causative drug was administered how long prior to the onset of the prodrome?
5-28 days
patients with sjs/ten who are immobile in bed should receive
LMWH as prophylactic anticoagulation against VTE
during acute phase of sjs/ten, patients in whom enteral nutrition cannot be established may benefit from
ppi to protect against upper GI stress ulceration
what kind of lubricant eye drops recommended for patients with sjs/ten?
non-preserved
topical corticosteroid drops in sjs/ten
reduce ocular damage in the acute phase, but can mask signs of corneal infection and should be used with caution in presence of a corneal epithelial defect
minoxidil, cannot be used to grow hair if
hair follicles are no longer present
- primary function is to prevent and slow down hair loss
- hair regrowth is more of a side effect
2 types of sunscreen
physical: reflect and scatter light, prevent uv radiation from penetrating the skin
chemical: absorb uv radiation, preventing it from reaching the deeper layers of the skin
examples of common active ingredients of chemical sunscreens
- Cinnamates
- Drometrizole trisiloxane
- Octocrylene
- Oxybenzone
- Avobenzone (butyl methoxydibenzoylmethane)
- Octinoxate
- Salicylates
- Terephthalylidene dicamphor sulfonic acid
common active ingredients of physical sunscreens
zinc oxide and titanium dioxide
if you have oily or acne-prone skin, what type of sunscreen formulation to avoid?
greasy
other ways to maximise sun protection, other than using suncreen
- Avoiding the sun when it is strongest between 11am to 3pm.
- Wearing protective clothes under the hot sun. Even if you are under the shade on the beach, sunrays can be reflected off the sand and cause a burn on your skin.
SPF
Sun Protection Factor: index to indicate the degree of protection from UVB
UVB
type of UV radiation that is more likely to cause sunburn
the higher the SPF
the longer the duration of protection
A sunscreen with SPF ___ or higher should be applied frequently to maintain protection
30
apply the sunscreen at least ____ before going into the sun
half an hour
with a non-water resistant sunscreen, reapply
after every swim or heavy perspiration, but make sure our skin is dry first
with a water resistant sunscreen, reapply
every 2 hours or every hour if you have been swimming
do you have to wear sunscreen on cloudy or overcast days?
yes, the sunrays are as damaging to your skin on hazy days as they are on sunny days
do you have to wear sunscreen at high altitudes?
yes, there is less atm to absorb the sunrays so exposure is higher and risk of sun burning is also higher
oxybenzone in kids
has been found in other studies to be associated with (but not necessarily to cause) lower testosterone levels in adolescent boys
how old must you start using sunscreen adily?
6 months old
sunscreen ingredient to avoid in children
PABA, oxybenzone
- generally go for physical sunscreen: low risk of sensitisation, irritation, and skin peentration potential
