A 35-year-old man presents to the dermatology clinic for evaluation of multiple erythematous papules and nodules affecting his chest, arms, and upper back. He is receiving institutional therapy for opioid use disorder. His medical history also is positive for adjustment disorder with mixed anxiety and depression. The patient’s medications include olanzapine and sertraline. Physical examination of the lesions reveals excoriations. The patient expresses indifference to the condition and states that occasionally his “skin is itchy.”
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Prurigo nodularis was first described in a textbook in 1909 by James Nevins Hyde, who identified an intensely pruritic disorder characterized by hyperkeratotic papules and nodules that are often excoriated and/or eroded.1 The condition is the result of chronic repetitive trauma to the skin induced by incessant scratching and rubbing. The cause is unknown.
The suggested underlying pathophysiology includes small fiber neuropathy or decreased nerve fiber density.2,3 Prurigo nodularis may be associated with underlying medical conditions such as atopic dermatitis and renal failure, and a significant number of cases are linked to psychiatric disorders.4
The goal of therapy is to improve quality of life by mitigating the chronic itch-scratch cycle. There are no US Food and Drug Administration-approved treatments for prurigo nodularis; however, options with reported varying success include moisturizers; topical, intralesional, and systemic steroids; calcineurin inhibitors; phototherapy; antidepressants, and naltrexone.5-7 More severe cases have been treated with cyclosporine, gabapentin, and thalidomide. A study by Ständer et al reported that a subcutaneous injection of the interleukin-31 inhibitor nemolizumab induced significant improvement of prurigo nodularis.8 Activation of this proinflammatory cytokine is thought to play a key role in the pathogenesis of prurigo nodularis.
Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
1. Hyde JN. A Practical Treatise on Diseases of the Skin for the Use of Students and Practitioners. 8th ed. Lea Brothers & Co; 1909:174-175. https://archive.org/stream/practicaltreatis00hydeuoft?ref=ol#page/n5/mode/2up/search/Prurigo+nodularis
2. Pereira MP, Pogatzki-Zahn E, Snels C, et al. There is no functional small-fiber neuropathy in prurigo nodularis despite neuroanatomical alterations. Exp Dermatol. 2017;26(10):969-971.
3. Schuhknecht B, Marziniak M, Wissel A, et al. Reduced intraepidermal nerve fibre density in lesional and nonlesional prurigo nodularis skin as a potential sign of subclinical cutaneous neuropathy. Br J Dermatol. 2011;165(1):85-91.
4. Pereira MP, Hoffmann V, Weisshaar E, et al; EPP Consensus Conference Participants 2017. Chronic nodular prurigo: clinical profile and burden. A European cross-sectional study [published online February 20, 2020]. J Eur Acad Dermatol Venereol. doi: 10.1111/jdv.16309.
5. Kwatra SG. Breaking the itch-scratch cycle in prurigo nodularis. N Engl J Med. 2020;382(8):757-758.
6. Huang AH, Canner JK, Kang S, Kwatra SG. Analysis of real-world treatment patterns in patients with prurigo nodularis. J Am Acad Dermatol. 2020;82(1):34-36.
7. Phan NQ, Bernhard JD, Luger TA, Ständer S. Antipruritic treatment with systemic μ-opioid receptor antagonists: a review. J Am Acad Dermatol. 2010;63(4):680-688.
8. Ständer S, Yosipovitch G, Legat FJ, et al. Trial of nemolizumab in moderate-to-severe prurigo nodularis. N Engl J Med. 2020;382(8):706-716.