Nodular prurigo is a chronic dermatologic condition characterized by intense pruritus and the presence of multiple hyperkeratotic nodules, predominantly distributed on the extremities.
Epidemiology
The condition commonly affects patients with a history of moderate to severe atopic dermatitis—seen in 3 out of 5 cases—but is also associated with:
- Chronic kidney disease (CKD)
- Liver failure
- Neuropsychiatric disorders (e.g., depression, obsessive-compulsive disorder)
- HIV infection
The age of onset is typically between 20 and 60 years and occurs equally in both sexes.
Pathogenesis
The disease is driven by type 2 inflammation, primarily mediated by interleukins 4, 13, and 31. These cytokines enhance the perception of itch—particularly neuropathic itch—leading to mechanical trauma caused by scratching. This activates fibroblasts, resulting in lichenification and nodule formation.
Morphology
Lesions appear as multiple, symmetrical, lichenified, and elevated nodules, often grouped and located on the shins and forearms, especially on the extensor surfaces (less commonly on the trunk or face). They vary in:
- Number:Few to many
- Form:From small papules to large firm nodules
- Size:1–3 cm
Early lesions are erythematous and later evolve into hyperpigmented nodules with scaling and crusts from intense scratching.
Clinical Presentation
Patients report intense, often nighttime, itching that is distressing and leads to scratching-induced trauma. This perpetuates lesion formation and, in chronic phases, results in scarring and post-inflammatory hyperpigmentation.
Course
The disease follows a chronic and persistent course with flare-ups and remissions. It is frequently associated with high psychological stress and significantly impairs quality of life.
Diagnosis
Diagnosis is clinical, based on lesion morphology, distribution, and the patient’s symptoms.
Complications
- Secondary infections due to lesion contamination
- Scarring and post-inflammatory hyperpigmentation
- Major psychological burden and reduced quality of life
Therapeutic Approaches
Topical Treatments:
- Potent corticosteroids (creams or ointments) applied under occlusion
- Topical calcineurin inhibitors (e.g., tacrolimus) and vitamin D analogs (e.g., calcipotriol) have shown promising results
- Intralesional corticosteroid injections (typically triamcinolone)
- Emollients and moisturizers to reduce scaling and mildly relieve pruritus
- Capsaicin applied at night has been reported to reduce pruritus and the formation of new lesions
Systemic Treatments:
- Antihistamines:Moderate efficacy, particularly for nocturnal pruritus
- Cyclosporine:Highly effective, though relapses may occur after discontinuation
- Methotrexate:Also effective, but contraindicated in women of reproductive age or those planning pregnancy
- Gabapentin/Pregabalin:Can be co-administered with other treatments to reduce neuropathic itch
Emerging Treatments:
- Dupilumab:Subcutaneous administration every 2 weeks. Blocks IL‑4/IL‑13 signaling via IL‑4Rα. Highly effective in reducing both pruritus and lesion count.
- JAK1 inhibitors:Agents like upadacitinib and abrocitinib, taken orally once daily, demonstrate rapid onset and high response rates, especially in refractory cases.
- Nemolizumab:Targets the IL‑31 receptor. Currently under clinical investigation. Shows reduction in itch and improvement in quality of life.
- Omalizumab:Anti-IgE monoclonal antibody used off-label in select cases of recurrent or allergen-triggered pruritic eruptions, with reported favorable outcomes.
At Optimum Dermatology, our expert physicians and innovative treatments ensure the best possible results.
