How to tell EM and SJS apart! (target vs. targetoid lesions)

One of the most concerning rashes in #dermatology is Stevens Johnson Syndrome (SJS), but how can you appropriately diagnose that when Erythema Multiforme (EM) looks so similar?! Getting it right is so important since EM is usually self limited and SJS can be deadly.
Join Steven as he walks you through the morphology and key differences between the two skin diseases!
Thanks for VisualDx and DermnetNZ for the example photos here.
#medicaleducation #morphology

[@rumit9946]

Thanks so much for the excellent clarification

[@Luchaux]

Great advice tyvm !

[@NaifahAlmheiri]

What about atypical EM vs SJS ? do we go by palpation ? as in in SJS we would appreciate flat macules

[@renani829]

Thanks so much for the clarity..
I have a question . Can EM major turn to SJS in future or are these two different and only have some similar histo pathological features which confuse. Can nikolsky sign be seen in EM major too?

[@mrandmrsheme]

Great questions. Both can have similar pathology findings, and bad EM Major can also be nikolsky negative. EM should not turn into SJS. That said, I've seen very severe EM major that is basically treated like SJS.

[@shelly9959]

Please do more teaching videos!

[@Fomites]

Thanks Steven. Good video.

[@bahojaa878]

Wonderful explanation. Thanx

[@ahmedmoneeb5166]

great! now every time I'm going to order from Target I'll get flashbacks of SJS haha
But seriously, great illustration, thank you!

[@johnjjmoon]

Very helpful, thank you.

[@sareennar6860]

My dad has reoccurring blisters on hands, he’s on constant penicillin for his hip. No doctor can diagnose it. May dm you a pic?

[@Jasmine-gp6ui]

Can erythema multiforme show up as just one lesion in one part of the body and one lesion in another? Or is it always many lesions?

[@mrandmrsheme]

That'd be unusual, but I guess not impossible. It's usually a true eruption with multiple lesions.

[@zahraamohamned3396]

Hello Dr,
Could u post more educational videos?

[@SuperVampireheart666]

What causes skin reactions? I had one on my hands and feet and effected my eyes a bit it wore off but it hurt a lot from Abilify. Is it to do with race and genetics also do you inherit it from parents? I am white British but I think I may have other race in me. I have lots of light scar marks on my palms and it made my big toes infected also I seem to react badly to most medications that are of antipsychotic or blood pressure I get serious nerve like damage why is this? I can only handle certain meds that are mild ones please help me understand what is wrong I also have sleep apnea all my life even when I was young and slim. Also my eyes have had problems since birth thanks.