Matteo Megna 1, Elisa Camela 2, Angelo Ruggiero 1, Teresa Battista 1, Fabrizio Martora 1, Sara Cacciapuoti 1, Luca Potestio. Clin Cosmet Investig Dermatol. 2023 Jun 28:16:1677-1690. doi=10.2147/CCID.S407812

Generalized pustular psoriasis (GPP) is a severe and rare form of psoriasis, being a potentially life-threatening condition, characterized by recurring episodes or flares of widespread cutaneous erythema with macroscopic sterile pustules. An irregular innate immune response is linked to GPP, which is considered an auto-inflammatory disorder, while innate and adaptive immunopathogenic responses are involved in psoriasis pathogenesis. In consequence, different cytokine cascades have been suggested to be mainly involved in the pathogenesis of each different psoriasis form, with the interleukin (IL)23/IL17 axis implied in plaque psoriasis, and the IL36 pathway in the GPP. As regards GPP treatment, conventional systemic drugs available for plaque psoriasis are usually used as the first-line treatment option. However, contraindications and adverse events often limit the use of these therapies. In this scenario, biologic drugs may represent a promising treatment option. To date, even if 12 different biologics have been approved for plaque psoriasis, none of these is approved for GPP where they are employed off-label. Recently, spesolimab, an anti-IL36 receptor monoclonal antibody, has been recently approved for GPP. The purpose of this article is to assess the current literature about the use of biological therapies for the treatment of GPP to establish the basis for a shared GPP management algorithm.

Biju Vasudevan ¹, Pankaj Das ¹, Siddharth Bhatt ¹ Indian J Dermatol Venereol Leprol. 2023 May 28:1-11.

Pustular psoriasis is a distinct subset of psoriasis that presents with involvement of the skin in the form of sterile pustules along with systemic manifestations. Though it has been conventionally grouped under the umbrella of psoriasis, recent research has shed light on its pathogenetic mechanisms associated with the IL-36 pathway, which is distinct from conventional psoriasis. Pustular psoriasis in itself is a heterogeneous entity consisting of various subtypes, including generalized, localized, acute, and chronic forms. There is confusion regarding its current classification as entities like deficiency of IL-36 antagonist (DITRA) which are closely related to pustular psoriasis both in their pathogenetic mechanism and its clinical manifestations, are not included under pustular psoriasis. Entities like palmoplantar pustulosis, which presents with similar clinical features but is pathogenetically distinct from other forms of pustular psoriasis, are included under this condition. Management of pustular psoriasis depends upon its severity; while some of the localized variants can be managed with topical therapy alone, the generalized variants like Von Zumbusch disease and impetigo herpetiformis may need intensive care unit admission and tailor-made treatment protocols. The advent of newer biologics and better insight into the pathogenesis of pustular psoriasis has opened the way for newer therapies, including tumor necrosis factor-alpha inhibitors, interleukin-1 inhibitors, interleukin-17 inhibitors, and granulocyte monocyte apheresis. It continues to be an enigma whether pustular psoriasis is actually a variant of psoriasis or an entirely different disease entity, though we feel that it is an entirely different disease process.

Pustular psoriasis: A distinct aetiopathogenic and clinical entity – PubMed (nih.gov)

Pustular psoriasis: A distinct aetiopathogenic and clinical entity – Indian Journal of Dermatology, Venereology and Leprology (ijdvl.com)

Mariko Seishima ^1 2, Kento Fujii ³, Yoko Mizutani ³ Am J Clin Dermatol 2022 Jun 15. doi: 10.1007/s40257-022-00698-9.

Generalized pustular psoriasis (GPP) is a rare, severe neutrophilic skin disease characterized by sudden widespread eruption of sterile pustules with or without systemic symptoms. GPP may be life threatening in cases with severe complications such as cardiovascular failure, acute respiratory distress syndrome, and serious infections. Impetigo herpetiformis (IH) is a GPP that is induced and exacerbated by pregnancy and occurs most frequently during the last trimester. IH may result in poor or fatal neonatal outcomes, including placental insufficiency, fetal abnormalities, stillbirth, and early neonatal death. Most patients have prompt remission in the postpartum period; however, earlier appearance and more severe symptoms are observed during subsequent pregnancies. Appropriate treatment and close monitoring of the mother and fetus are vital for the management of patients with IH. Particular attention is required for the management of patients with IH to avoid an influence on the fetus. However, data regarding treatments for GPP in pregnant women are sparse. Over the last decade, many patients with IH have been treated with cyclosporine, corticosteroids, tumor necrosis factor-α inhibitors, interleukin (IL)-17 and IL-12/23 inhibitors, and granulocyte and monocyte adsorption apheresis (GMA). GMA may be an important option for patients with IH as it is presently one of the safest available therapeutic options, but there have been no reports to fully confirm its safety in pregnant patients with GPP. Alternatively, based on recent advances in the understanding of the role of the IL-36 axis in the pathogenesis of GPP, biologic agents that target the IL-36 pathway may demonstrate promising efficacy in IH.

Generalized Pustular Psoriasis in Pregnancy: Current and Future Treatments – PubMed (nih.gov)

Masashi Akiyama 

J Dermatol Sci 2022 Jan;105(1):11-17. doi: 10.1016/j.jdermsci.2021.11.009. 

Pustular psoriasis is a chronic inflammatory skin disease characterized by erythematous plaques with sterile pustules. It includes the distinct clinical entities generalized pustular psoriasis (GPP), acrodermatitis continua of Hallopeau (ACH) and palmoplantar pustular psoriasis (PPPP). Recently clarified pathomechanisms of pustular psoriasis indicate that hyperactivation of the skin innate immunity, including of the IL-1/IL-36 axis, plays an important role in the pathogenesis of pustular psoriasis. Autoinflammatory keratinization disease (AiKD) is the umbrella clinical entity for inflammatory keratinization disorders with genetic autoinflammatory pathomechanisms, and pustular psoriasis is a representative AiKD. To date, mutations/variants in five genes-IL36RN, CARD14, AP1S3, MPO and SERPINA3-have been reported to be genetic causative or predisposing factors for pustular psoriasis. The pathogenic mechanisms induced by the mutations/variants in these genes are all closely related to the excessive activation of skin innate immunity and autoinflammation. A number of biologics (e.g., tumor necrosis factor inhibitors, IL-17/IL-17 receptor inhibitors and IL-23 inhibitors) and granulocyte and monocyte adsorption apheresis are used to treat pustular psoriasis. Recently, based on novel information on the pathomechanisms of pustular psoriasis, which are mainly associated with autoinflammation, inhibitors of several pathogenic pathways, including of the IL-1, IL-36, IL-8 and granulocyte colony-stimulating factor signaling pathways, have been studied as emerging treatments.

Pustular psoriasis as an autoinflammatory keratinization disease (AiKD): Genetic predisposing factors and promising therapeutic targets – PubMed (nih.gov)

Pustular psoriasis as an autoinflammatory keratinization disease (AiKD): Genetic predisposing factors and promising therapeutic targets – Journal of Dermatological Science (jdsjournal.com)