Atopic Dermatitis (AD) vs Allergic Contact Dermatitis (ACD): Stepwise Management, Prescription Pearls, and Clinical Algorithms
- Mayta
- Jun 14
- 4 min read
Atopic Dermatitis (AD) vs Allergic Contact Dermatitis (ACD)
(Natural history → severity classification → stage-directed topical and systemic treatment ladders → RDU prescription examples & high-yield pearls)
1 Pathophysiology Snapshot
Key element | Atopic Dermatitis (AD) | Allergic Contact Dermatitis (ACD) |
Immune bias | Th2-skewed (IL-4, IL-13, ± IL-31) | Type IV delayed T-cell hypersensitivity (Th1 → IFN-γ) |
Barrier integrity | Congenitally leaky (↓ filaggrin → ↑ TEWL) | Intact until allergen re-exposure |
Recurrence driver | Endogenous barrier defect ⇒ chronic relapsing course | Continued / intermittent allergen contact |
2 Severity & Stage Classification
2.1 Atopic Dermatitis
Clinical score | Mild | Moderate | Severe |
SCORAD | < 25 | 25–50 | > 50 |
EASI | < 7 | 7–21 | > 21 |
Morphologic stages: Acute flare (erythema, vesicle, ooze) → Sub-acute (papule, crust) → Chronic (lichenification, fissure).
2.2 Allergic Contact Dermatitis
Stage | Morphology | Typical duration |
Acute | Vesicle, weep, edema | 1–14 days |
Sub-acute | Crust, scale, scattered papules | 2–6 weeks |
Chronic / Lichenified | Thick plaque, fissure, dyspigmentation | > 6 weeks / repeated flares |
Overall severity: % BSA involved and functional impact (e.g., occupational hand eczema).
3 Step-Up Topical Drug Ladder
3.1 Atopic Dermatitis (2023 AAD / AAAAI)
Step | When to use | Core prescriptions (RDU format) |
0 Foundation | Every patient | • Emollient (petrolatum/ceramide) liberal ≥ BID • Trigger avoidance |
1 Mild / maintenance | SCORAD < 25, localised | Hydrocortisone 1 % cream thin BID topical × 7 days |
2 Moderate flare | SCORAD 25–50 or face/flexures | Triamcinolone 0.1 % ointment BID × 10 d ＋ Tacrolimus 0.03 % ointment BID up to 6 wk |
3 Severe chronic / frequent flare | SCORAD > 50, ≥10 % BSA, ≥4 disturbed-sleep nights/wk | Clobetasol 0.05 % cream BID × 7 d → taper ＋ NB-UVB phototherapy |
4 Systemic conventional | Failure / intolerance step 3 | Cyclosporine 3 mg/kg/d PO BID × 12–16 wk / Methotrexate 15 mg PO weekly + folate |
5 Targeted systemic | Refractory or steroid-sparing | Dupilumab 600 mg SC load → 300 mg SC q2 wk / Tralokinumab 300 mg SC q2 wk / Upadacitinib 15–30 mg PO qd |
Pruritus control: Hydroxyzine 25 mg PO hs (child 0.5–1 mg/kg).
3.2 Allergic Contact Dermatitis – Evidence-Based Ladder
Stage / Severity | Drug approach | Example (RDU) |
Acute, localised (<10 % BSA) | Medium-potency TCS | Betamethasone valerate 0.1 % cream BID topical × 10 d |
Acute, widespread / facial edema | ① Burow wet compress ② High-potency TCS ③ Short oral steroid if > 20 % BSA or peri-orbital | Prednisone 0.75 mg/kg/d PO × 5 d → taper 10 mg q2 d (total 14 d) |
Sub-acute / Chronic lichenified | Potent TCS under occlusion ± TCI eyelid; nightly sedating antihistamine | Clobetasol 0.05 % ointment BID × 7 d on / weekend pulse |
Severe hand / refractory | Systemic immunomodulator | Alitretinoin 30 mg PO qd (6 mo) or Azathioprine 2 mg/kg/d PO |
Maintenance / Prevention | All patients | Patch-test-guided allergen avoidance ＋ Barrier cream / gloves ＋ Emollient after wash |
4 When & How to Introduce Oral Therapy
Indication (either disease) | First-line oral agent | Key adult regimen | Safety points |
Severe itch impacting sleep | Hydroxyzine | 25–50 mg PO hs (max 100 mg/d) | Sedation; avoid alcohol, driving; ECG elderly |
Acute severe flare (> 10 % BSA) | Prednisone | 0.5–1 mg/kg/d PO × 5–7 d → taper same length | Limit courses (<2/yr); check BP, glucose |
Chronic moderate-severe AD | Cyclosporine | 3–5 mg/kg/d PO divided BID (≤ 6 mo) | BP, creatinine q2 wk → monthly |
Steroid-sparing long-term AD | Methotrexate | 15–25 mg PO weekly + folate | CBC, LFT q4–8 wk |
Refractory AD | Dupilumab | 600 mg SC load → 300 mg q2 wk | Conjunctivitis (10 %); no routine labs |
Chronic hand-ACD unresponsive | Alitretinoin | 30 mg PO qd × 24 wk | Teratogenic; monitor lipids, LFT |
Always combine with proactive topical weekends + daily emollient.
5 Integrated Escalation Algorithm (Adult)
6 Unified RDU Prescription Templates
Prednisone (30 mg)
1 tab × 1 PO qd for 7 days, then taper by 10 mg every 2 days (total 14 days).
Clobetasol 0.05 % ointment
apply thin BID topical to plaques for 7 days, then once daily 7 days.
Tacrolimus 0.03 % ointment
apply BID topical to face/flexures starting day 8 for 6 weeks.
Hydroxyzine 25 mg
1 tab PO hs prn itch (max 100 mg/d).
Cyclosporine 100 mg caps
3 mg/kg/day PO divided BID; titrate to trough 100–150 ng/mL; planned 16-week course.
Dupilumab 300 mg/2 mL
600 mg SC loading, then 300 mg SC q2 wk until week 16 review.
7 High-Yield Examination Pearls
Barrier repair + trigger control remain first-line for both conditions.
Topical steroid potency = site × stage (low face, high lichenified limbs).
Hydroxyzine is night-time only; switch to non-sedating agents for daytime.
Patch testing is obligatory in ACD; without allergen eviction, relapse is inevitable.
Short oral corticosteroids (≤ 2 weeks) are rescue only; chronic use is a red-flag answer.
Cyclosporine is still first systemic option for chronic severe AD when biologics unavailable.
Dupilumab/JAK inhibitors now precede broad immunosuppressants in updated AD guidelines.
Always screen TB, hepatitis, HIV before starting systemic immunosuppression.
Document EASI/SCORAD before & after therapy—quality-of-care metric often examined.
In any algorithm, identify & avoid allergen sits at the root for ACD; pharmacotherapy is only a bridge.
Quick Reference Cheat-Sheet
Step | AD Core Drug | ACD Core Drug | Monitoring |
Mild | Hydrocortisone | Betamethasone valerate | — |
Mod | Triamcinolone ± Tacrolimus | Clobetasol pulses | Skin atrophy caution |
Severe | Clobetasol + NB-UVB | Prednisone burst | Phototherapy schedule / glucose |
Steroid-sparing | Cyclosporine / MTX | Alitretinoin / AZA | BP, CBC, LFT |
Targeted | Dupilumab / JAKi | — (off-label) | Lipids, TB screen |
Use this synthesized guide for bedside decisions, OSCE stations, and prescription writing with confidence.
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