erythema multiforme vs marginatum vs migrans

[natsume]

I haven't found a good source to differentiate the 3 morphologically. It seems like all three have red border w/ central pallor. How do you differntiate them grossly? Or do we have to rely on clinical info like rheumatic fever (marginatum), tick bite (migraines), infection/drug (multiforme)?

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[Transposony]

Yes, you are right.
Clinical context is the key.
This might help.

 

[Robotic Dock]

Hi

Based on clinical presentation:

-necrolytic erythema migrans= glucagonoma

-erythema nodusum: (usu.) granulomatous dis.

-Erythema marginatum: Rheu. Fever

Thank you for the post.

 

[Robotic Dock]

Erythema multiforme:

Usu. drug reactions.

 

[thehundredthone]

I haven't found a good source to differentiate the 3 morphologically. It seems like all three have red border w/ central pallor. How do you differntiate them grossly? Or do we have to rely on clinical info like rheumatic fever (marginatum), tick bite (migraines), infection/drug (multiforme)?

Erythema migrans is called so because the rash appears to migrate outward with a central clearing. Hence if you observed the rash for some days you would be able to differentiate migrans from multiforme and marginatum. It would also be a single lesion at the site of the tick bite (although in disseminated infections they can be multiple). Erythema multiforme has multiple lesions, which are raised (and pruritic). Erythema marginatum is found mostly on extensor surfaces, ring like but not raised (and not pruritic). So yes, clinical context is always useful (and often necessary).