What are the treatment options for prurigo nodularis?

Treatment Options for Prurigo Nodularis

Narrowband UVB phototherapy is the recommended first-line treatment for prurigo nodularis, with topical corticosteroids and antihistamines as adjunctive therapies. 1

Diagnosis and Clinical Features

Prurigo nodularis (PN) is characterized by:

• Firm, nodular lesions
• Intense pruritus lasting at least 6 weeks
• Evidence of repeated scratching, picking, or rubbing 2
• Papulonodular pruriginous eruption that can be symmetrically distributed 3

Treatment Algorithm

First-Line Therapies:

1. Narrowband UVB (TL-01) Phototherapy:

   • Highly effective for nodular prurigo 1
   • Standard psoriasis treatment approach can be applied
   • Requires multiple sessions (typically 2-3 times weekly)

2. Topical Therapies (to be used concurrently with phototherapy):

   • Potent topical corticosteroids:

     • Applied twice daily to affected areas
     • Consider occlusion for enhanced penetration

   • Topical calcineurin inhibitors (tacrolimus, pimecrolimus):

     • Alternative for sensitive areas or when steroid-sparing is needed
     • Apply twice daily

3. Oral Antihistamines:

   • Non-sedating antihistamines for daytime use
   • Consider sedating antihistamines at night for sleep disturbance 4

Second-Line Therapies:

For patients who fail to respond to first-line treatment after 4-6 weeks:

1. Systemic Immunomodulators:

   • Cyclosporine: Effective for severe cases 5
   • Methotrexate: Alternative immunosuppressive option 5

2. Neuromodulatory Medications:

   • Gabapentin/Pregabalin: Effective for neurogenic pruritus 4, 5
   • Thalidomide: Highly effective but limited by side effects 5, 6

3. Biologic Therapies:

   • Dupilumab: Reduces pruritus and improves lesion appearance with fewer side effects than other systemic options 6

Special Considerations

• Combination therapy targeting both neural and immunologic components of pruritus is often more effective than monotherapy 2
• Identify and treat underlying causes: Various dermatologic, systemic, neurologic, or psychiatric conditions can trigger prurigo nodularis 3
• Monitor for phototherapy side effects: Short-term erythema and long-term photoaging

Treatment Response Assessment

• Evaluate response after 2-4 weeks of treatment
• Assess both pruritus intensity and nodule appearance
• Consider treatment modification if inadequate response after 6-8 weeks

Pitfalls and Caveats

1. Avoid prolonged use of high-potency topical steroids without supervision due to risk of skin atrophy
2. Be aware of potential side effects of systemic therapies:
   • Thalidomide: peripheral neuropathy, teratogenicity
   • Cyclosporine: nephrotoxicity, hypertension
   • Methotrexate: hepatotoxicity, bone marrow suppression
3. Consider patient comorbidities when selecting therapy:
   • Phototherapy may not be suitable for patients with photosensitivity disorders
   • Thalidomide is contraindicated in pregnancy
   • Immunosuppressants require careful monitoring in elderly patients

The treatment of prurigo nodularis often requires persistence and may need combination approaches to effectively break the itch-scratch cycle that perpetuates the condition.