Skip to main content
ChenDermatologist
ChenDermatologist
Dr. Chen Yi-Jia · Dermatology Notes
English version. Prefer Traditional Chinese? Switch to Chinese
Patient guide · Prescription Per TDA 2024 consensus · Updated 2026-05-07

Prurigo nodularis — complete patient guide
Refractory itch, the dupilumab and nemolizumab era

Prurigo nodularis (PN) is a chronic, refractory, intensely pruritic skin disease characterized by symmetrically distributed, firm, well-demarcated nodules (0.5-3 cm) on the extensor extremities, back, and buttocks. Most often driven by the itch-scratch cycle. Recent advances: dupilumab and nemolizumab have transformed treatment for moderate-to-severe disease.

Note:Refractory itch accompanied by weight loss, fever, or lymphadenopathy requires evaluation for underlying malignancy (especially cutaneous T-cell lymphoma); please consult dermatology or hematology-oncology.

What is Prurigo Nodularis?

Prurigo nodularis (PN) is a chronic, treatment-resistant pruritic skin disease characterized by multiple, symmetrically distributed, firm, well-demarcated nodules (0.5-3 cm in diameter), typically on the extensor surfaces of the limbs, back, and buttocks. The pathognomonic "butterfly sign" reflects sparing of the upper-mid back where the patient cannot reach to scratch. PN is the prototypical phenotype of chronic prurigo per 2018 EADV nomenclature.

Diagnostic Criteria (2018 EADV / TDA 2024)

PN is a clinical diagnosis requiring all three:

  1. Chronic pruritus ≥ 6 weeks
  2. History or current evidence of scratching behavior
  3. Multiple, localized, nodular pruriginous lesions

Differential diagnosis:

  • Nodular scabies (mite scrapings, household contacts)
  • Cutaneous T-cell lymphoma (MF/SS) — biopsy + IHC
  • Pemphigoid prurigoides (anti-BP180/BP230, DIF)
  • Reactive perforating collagenosis (especially in CKD)
  • HIV, lymphoma, paraneoplastic pruritus — investigate per clinical clues

Severity Assessment

  • WI-NRS (Worst Itch NRS): 0-10; ≥ 7 severe; response = ≥ 4-point reduction
  • IGA-PN: 0-4; goal is 0 (clear) or 1 (almost clear)
  • DLQI: PN typically > 15 (severe QoL impact)

Comorbidity Workup (TDA 2024 strongly recommended)

  • Baseline labs: CBC, CMP, TSH, HbA1c, HBV/HCV serology, HIV (if at risk), ferritin
  • Coexisting skin conditions: AD (30-50% co-occur), psoriasis, lichen planus
  • Systemic disease: CKD (uremic pruritus), cholestatic liver disease, diabetes, hyperparathyroidism, lymphoma (CTCL, Hodgkin), myeloproliferative neoplasms
  • Neuropathy: diabetic, brachioradial pruritus, peripheral sensory neuropathy
  • Psychiatric: anxiety, depression, OCD — scratching may be reinforced by mood disorders
  • Routine allergy testing not required — IgE-mediated mechanisms are not central

Stepwise Treatment (TDA 2024)

Step 1 — basic care + topicals

  • Daily emollients (ceramide, hyaluronic acid; apply within 3 minutes of bathing)
  • Trim nails short; cotton gloves at night to interrupt scratching
  • Mid- to high-potency topical corticosteroids; intralesional triamcinolone for refractory nodules
  • Topical calcineurin inhibitors (tacrolimus, pimecrolimus) — for steroid-sensitive sites or maintenance
  • Topical capsaicin 0.025-0.075% (refractory cases)
  • 2nd-gen antihistamines: generally not effective for PN unless co-existing urticaria/AD

Step 2 — systemic therapies

  • Gabapentinoids: gabapentin 100-300 mg → up to 3600 mg/d in TID; pregabalin 75 mg BID → up to 600 mg/d
  • SSRI/SNRI: sertraline, mirtazapine, paroxetine; mirtazapine sedation aids nocturnal itch
  • Naltrexone 50 mg/d for cholestatic itch / refractory cases
  • Methotrexate / cyclosporine / azathioprine / MMF — off-label when biologics unavailable
  • NB-UVB 2-3 ×/wk for widespread PN
  • Oral corticosteroids only for short-term bridging

Step 3 — biologics & new agents

Dupilumab (FDA-approved 2022 for PN)

Mechanism: anti-IL-4Rα mAb, blocks IL-4 / IL-13 → reduced Th2 inflammation and neural sensitization.

  • Indication: adults ≥ 18 with moderate-severe PN
  • Dosing: 600 mg loading → 300 mg SC q2w
  • Pivotal trials: LIBERTY-PN PRIME / PRIME 2 (Yosipovitch 2023, NEJM/Nat Med)
  • 24-week efficacy: WI-NRS ≥4-point reduction 60.0% vs 18.4% placebo; IGA-PN 0/1 48.0% vs 18.4%
  • 52-week: most responders maintain response
  • Common AEs: conjunctivitis (~10-15%), injection-site reactions, mild eye dryness; no routine bloodwork required
  • Co-morbid benefits: also treats AD, asthma, CRSwNP, eosinophilic esophagitis

Nemolizumab (FDA-approved 2024 for PN)

Mechanism: anti-IL-31 receptor (IL-31R) mAb. IL-31 is the dominant "itch cytokine" in PN.

  • Indication: adults ≥ 18 with moderate-severe PN (FDA approval 2024-08-13)
  • Brand: Nemluvio® (Galderma)
  • Dosing: 60 mg loading → 30 mg SC q4w (advantage: less frequent than dupilumab)
  • Pivotal trial: OLYMPIA 1 + 2 (Kwatra 2023, NEJM)
  • 16-week efficacy (OLYMPIA 2): PP-NRS ≥4-point reduction 56.3% vs 20.9%; IGA 0/1 37.7% vs 11.0%
  • Onset: clinical itch reduction within 1-2 weeks (faster than dupilumab)
  • Common AEs: headache, paradoxical eczema flare, conjunctivitis (some)

Future Therapies (in trials)

  • JAK inhibitors: oral abrocitinib, upadacitinib — early-phase data show pruritus improvement
  • NK1 antagonists: aprepitant, serlopitant — phase III mixed results
  • OX40/OX40L blockade: rocatinlimab, amlitelimab
  • KIT inhibitors: barzolvolimab — for CSU-PN overlap

Bottom Line — 4 Things

  1. Don't tolerate it: refractory pruritus is not "sensitive skin"; it's a real chronic disease. Early treatment prevents irreversible nodule formation.
  2. Find the trigger: CKD, liver disease, diabetes, lymphoma may be hidden — comorbidity screening is essential.
  3. Break the itch-scratch cycle: night gloves, short nails, emollients, gabapentinoids for sleep — give the skin time to heal.
  4. New drugs work: for moderate-severe refractory PN, dupilumab and nemolizumab have transformed outcomes with strong 52-week durability.