What is the treatment for prurigo nodularis?

Treatment for Prurigo Nodularis

Start with high-potency topical corticosteroids under occlusion combined with phototherapy (narrowband UVB), as these represent the most evidence-based first-line treatments for prurigo nodularis. 1, 2

First-Line Treatment Approach

Topical Corticosteroids

• Apply high-potency topical corticosteroids (such as clobetasol propionate) under occlusive dressing to maximize penetration into the hyperkeratotic nodules. 2, 3
• Corticosteroids show significantly improved efficacy when used under occlusion compared to open application, addressing the thick, lichenified nature of prurigo nodules. 2
• Treatment duration should be 3-4 times daily for up to 7 days maximum to avoid skin atrophy, then reassess. 4

Intralesional Corticosteroids

• For resistant individual nodules, inject intralesional triamcinolone acetonide (10-40 mg/mL) directly into lesions. 2, 3
• This provides targeted therapy for particularly stubborn nodules that fail topical treatment. 2

Phototherapy

• Initiate narrowband UVB (TL-01) phototherapy three times weekly using a standard psoriasis treatment protocol. 1
• The British Photodermatology Group reports case evidence supporting narrowband UVB for nodular prurigo, though the strength of recommendation is C with quality of evidence III. 1
• Major caveat: Relapse rates after phototherapy discontinuation are high, requiring maintenance therapy or transition to alternative treatments. 2

Second-Line Topical Treatments

Capsaicin

• Apply topical capsaicin 0.025% to 0.3% four to six times daily for sustained antipruritic effect. 5
• Capsaicin depletes substance P from cutaneous nerves, eliminating pruritus within 12 days in all treated patients in one study. 5
• Critical warning: Initial burning sensation and erythema (neurogenic inflammation) must be explained to patients, as these symptoms precede therapeutic benefit. 5
• The British Journal of Dermatology advises against capsaicin for generalized pruritus of unknown origin, but research specifically in prurigo nodularis demonstrates clear efficacy. 1, 5
• After discontinuation, pruritus returns in approximately 50% of patients within 2 months, necessitating continuous use. 5

Calcineurin Inhibitors

• Consider topical tacrolimus or pimecrolimus as steroid-sparing alternatives, particularly for facial or intertriginous lesions. 2, 6
• One randomized controlled trial supports topical pimecrolimus efficacy in prurigo nodularis. 2

Systemic Treatment Options

When topical treatments and phototherapy fail after 2-4 weeks, escalate to systemic therapy:

Anticonvulsants

• Gabapentin or pregabalin target the neuropathic component of pruritus in prurigo nodularis. 6, 7
• These agents address the neural dysregulation underlying the itch-scratch cycle. 6

Immunosuppressants

• Cyclosporine has demonstrated improvement in both skin appearance and pruritus intensity. 6, 3
• Consider thalidomide for refractory cases, though strict pregnancy prevention protocols are mandatory. 6, 3

Opioid Receptor Antagonists

• μ-opioid receptor antagonists (such as naltrexone) can be effective for the central pruritus component. 6

Lesion-Directed Destructive Therapies

Cryotherapy

• Cryotherapy offers a practical lesion-directed approach that circumvents adherence challenges and avoids systemic medication risks. 2
• This modality directly destroys individual nodules while potentially interrupting the local itch-scratch cycle. 2

Essential Supportive Care (All Patients)

• Apply emollients at least once daily to all affected skin regardless of specific treatment chosen. 4
• Avoid wool clothing and harsh soaps that trigger pruritus. 4
• Keep skin dry after bathing using clean, separate towels. 4

Treatment Algorithm

1. Weeks 1-2: High-potency topical corticosteroids under occlusion + emollients + trigger avoidance 2, 3
2. Weeks 2-4: Add narrowband UVB phototherapy three times weekly if inadequate response 1
3. Weeks 4-6: Add topical capsaicin 0.025-0.3% four to six times daily for persistent pruritus 5
4. Week 6+: Escalate to systemic therapy (gabapentin, cyclosporine, or naltrexone) if no improvement 6, 7
5. Adjunctive: Intralesional triamcinolone or cryotherapy for individual resistant nodules throughout treatment course 2, 3

Critical Monitoring Points

• Reassess after 2 weeks; if no improvement or worsening occurs, advance to the next treatment step. 4
• Investigate for underlying systemic diseases (chronic kidney disease, liver disease, hematologic disorders, HIV, thyroid dysfunction) that may perpetuate prurigo nodularis. 7, 3
• Document disease burden using body surface area involvement and pruritus intensity scales to objectively track response. 7