Timeline for Resolution of Erythema Multiforme After Stopping the Causative Agent
Erythema multiforme typically resolves within 4 weeks after discontinuing the offending medication or treating the underlying infection, with individual lesions remaining fixed for a minimum of 7 days. 1, 2
Expected Timeline for Resolution
Individual lesions remain fixed for at least 7 days, which distinguishes EM from urticaria where lesions resolve within 24 hours. 1 The complete disease course from onset to resolution typically spans 4 weeks after the causative agent is removed or the underlying infection is treated. 2
Initial Management Steps
Stop the offending medication immediately upon suspicion of drug-induced EM and document all medications taken over the previous 2 months to identify the culprit drug. 3
Treat any underlying infections, particularly herpes simplex virus or Mycoplasma pneumoniae, as these are the most common infectious triggers. 1, 4
Monitoring and Reassessment
Reassess patients at 2-week intervals until complete resolution occurs. 3
If there is worsening or no improvement after 2 weeks of stopping the causative agent and initiating symptomatic treatment, consider alternative diagnoses or complications. 5
Important Clinical Considerations
The 7-day minimum duration of individual lesions is a key diagnostic feature that helps differentiate EM from urticaria and guides expectations for resolution timing. 1 Lesions typically present symmetrically on the extremities and spread centripetally. 1
Severe mucosal involvement may require hospitalization for intravenous fluids and electrolyte repletion, which can extend the overall recovery timeline. 1, 4
Common Pitfall to Avoid
Do not confuse EM with Stevens-Johnson syndrome, as SJS requires more aggressive management and has a significantly worse prognosis. 3 SJS typically presents with widespread erythematous or purpuric macules with blisters, whereas EM presents with characteristic targetoid lesions. 1