This handout is for cutaneous drug eruption — morbilliform vs scar (dermatology lens). Your care team identified this based on: symmetric, blanching, morbilliform/maculopapular eruption 4–14 d after a new drug — the common (~90%) benign exanthematous drug eruption (wei/nelson jaad 2023 part i pmid 37516359; balakirski pmid 28412864).
Other reasons your team may use this plan: new high-risk culprit started in the scar window (β-lactam/sulfonamide 4–14 d morbilliform; allopurinol/aromatic anticonvulsant/sulfonamide/vancomycin 2–8 wk dress; aminopenicillin/macrolide <4 d agep) (sassolas alden pmid 20375998; kardaun regiscar pmid 23855313); morbilliform eruption plus any scar red flag — mucosal involvement, facial edema, fever, skin pain/tenderness, blistering/nikolsky, eosinophilia, organ derangement ("morbilliform that may be early scar") (wei/nelson jaad 2023 part ii pmid 37516356); painful dusky/targetoid skin + ≥2 mucosal sites + nikolsky/epidermal detachment → sjs/ten spectrum (route derm.sjs-ten.core.v1; parvathaneni ocul surf 2025 pmid 40541663).
Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.
| Medication | Starting dose | How | When | What it does |
|---|---|---|---|---|
| discontinue probable culprit + all non-essential cross-reactors | — | n/a | — | Sassolas ALDEN (PMID 20375998) + Wei/Nelson JAAD 2023 Part II (PMID 37516356) — identify the single most-probable culprit by latency window + ALDEN logic and stop it (plus cross-reactors); withdrawal is the universal cornerstone and, for SCAR, the dominant survival lever. |
| allergy-record + lifelong culprit/cross-reactor avoidance documentation | — | n/a | — | Wei/Nelson JAAD 2023 Part II (PMID 37516356) — document the suspected culprit class + cross-reactors in the allergy record before disposition; never re-challenge a SCAR culprit (Sassolas ALDEN PMID 20375998). |
| defined-scenario treat-through decision gate (benign morbilliform only) | — | — | — | Wei/Nelson JAAD 2023 Part I (PMID 37516359) — "treat-through" is acceptable ONLY for a mild isolated morbilliform eruption to an essential non-substitutable drug with NO SCAR features and close surveillance; any SCAR feature voids this gate. |
Plan: Cutaneous drug eruption — STOP-culprit-first + phenotype-stratified ladder (RegiSCAR / JAAD 2023 / ALDEN)
Contact your care team if any of the following happen:
Call 911 or go to the nearest emergency room right away if you have:
Lifelong culprit + cross-reactor avoidance card and allergy-record entry (highest-yield recurrence-prevention action). Pharmacogenomic counselling/HLA documentation where applicable (B*15:02/B*58:01/A*31:01). DRESS: structured long-term autoimmune-sequelae surveillance (thyroid, glucose) for ≥1–2 years and complete steroid taper. Patient/family education on never re-challenging the culprit class. Allergy/immunology referral for delabelling vs confirmed avoidance and for safe alternative selection.
Guideline: Wei/Nelson et al, JAAD 2023 DiHS/DRESS Part I (PMID 37516359) + Part II diagnosis & management (PMID 37516356) + Kardaun et al prospective RegiSCAR DRESS case definition/score (Br J Dermatol 2013, PMID 23855313) + Sassolas et al ALDEN drug-causality algorithm (Clin Pharmacol Ther 2010, PMID 20375998) + Parvathaneni et al SJS/TEN causality review (Ocul Surf 2025, PMID 40541663) + Halevy AGEP/EuroSCAR validation (Curr Opin Allergy Clin Immunol 2009, PMID 19458527) + CPIC HLA-B/HLA-A pharmacogenomic guideline (Clin Pharmacol Ther 2018, PMID 29392710) with Hung HLA-B*58:01 allopurinol (PNAS 2005, PMID 15743917) and McCormack HLA-A*31:01 carbamazepine (NEJM 2011, PMID 21428769); cyclosporine-in-DRESS evidence (Zita JMIR Dermatol 2023 PMID 37632913; Kirchhof JAMA Dermatol 2016 PMID 27438540); Balakirski cutaneous allergic drug-reaction review (Cutan Ocul Toxicol 2017, PMID 28412864)