Paradoxical Psoriasis

Cytokine blocking therapies have revolutionized the management of psoriasis and atopic dermatitis but can lead to the development of paradoxic psoriasis (PP). Patients treated with biologics should be closely monitored for the development of PP and other paradoxical eruptions (including inflammatory joint disease, inflammatory bowel disease, eczematous eruptions, lupus like eruptions, sarcoidal eruptions, and others) and occasionally the development of cutaneous T-cell lymphoma. Further understanding the immunologic mechanism of these processes will ultimately drive our understanding of and ability to predict and manage PPs.

Paradoxical psoriasis: The flip side of idiopathic psoriasis or an autocephalous reversible drug reaction?

Psoriasis is a common, chronic skin disease that results mainly from the complex interplay between T cells, dendritic cells, and inflammatory cytokines including TNF-α, IL-17, IL-12, and IL-23. Successful therapy with anti-cytokine antibodies has proved the importance of these key cytokines, especially TNF-α. During the anti-TNF-α treatment of classical idiopathic psoriasis, a small portion of patients develop new psoriasiform lesions. This contradictory phenomenon was named paradoxical psoriasis which resembles idiopathic psoriasis clinically but presents overlapped histological patterns and distinct immunological processes. In this review, we discuss the differences between idiopathic psoriasis and paradoxical psoriasis with an emphasis on their innate immunity, as it is predominant in paradoxical psoriasis which exhibits type I IFN-mediated immunity without the activation of autoreactive T cells and memory T cells. We also put up an instructive algorithm for the management of paradoxical psoriasis. The decision on drug discontinuation or switching of biologics should be made based on the condition of underlying diseases and the severity of lesions.

Adalimumab-Induced Paradoxical Psoriasis Treated with Biologics Targeting the IL-17/IL-23 Axis in Patients with Hidradenitis Suppurativa

BACKGROUND

Paradoxical psoriasis (PP) has been mainly described in patients receiving tumor necrosis factor-α (TNFα) inhibitors for inflammatory bowel disease or psoriasis vulgaris, while such data in the context of hidradenitis suppurativa (HS) are scarce. The purpose of this study was to demonstrate the course of PP and the underlying HS upon switching from adalimumab to a biologic agent targeting the interleukin (IL)-17/IL-23 axis.

METHODS

The electronic medical database of the outpatient department for HS of a tertiary hospital for skin diseases was searched to identify patients with moderate-to-severe HS under treatment with adalimumab, who developed PP and were switched to biological therapy with an IL-17 or IL-23 inhibitor between February 2016 and January 2022. Disease assessment scores were evaluated at baseline, at time of PP development, as well as six and 12 months thereafter.

RESULTS

Among the 83 patients who received adalimumab for the treatment of HS between February 2016 and January 2022, 10 patients (12%) developed paradoxical psoriasiform skin reactions after a median time of seven (range, 2-48) months. There were four females (40%) and six males (60%) with a median age of 42.5 (range, 33-56) years. Five patients presented with plaque psoriasis and five with palmoplantar pustulosis, while four had intertriginous and three nail involvement. In most of the patients, HS responded well to adalimumab at onset of PP. Eight patients were changed to secukinumab, one to ustekinumab, and one to risankizumab. HS further improved in all but 2 patients, one receiving secukinumab and one receiving risankizumab. In addition, all patients achieved improvement of PP.

CONCLUSION

Despite the small number of patients, this study provides support that patients with adalimumab-induced PP may benefit from biologics targeting the IL-17/IL-23 axis. Further studies are needed to establish the optimal therapeutic strategy of the anti-TNFα-induced PP in the context of HS.

Psoriasis induced by biological therapy

OBJECTIVE

To describe a multicentre case series of new onset or worsening of psoriasis in patients treated with biological drugs.

MATERIAL AND METHODS

Descriptive study. We reviewed the clinical history of patients with chronic inflammatory disease (CID) treated with biological drugs, who developed new onset or worsening of psoriasis during the follow-up period.

RESULTS

Twenty-six cases of paradoxical psoriasis (PP) were recorded. Ninety-three percent of the patients were treated with anti-TNFα and adalimumab was responsible for 50% of the cases. Only 5 patients had a personal history of psoriasis. The biological drug was discontinued in 13 patients. Lesion recurrence was more frequent when another anti-TNFα was reintroduced.

CONCLUSIONS

The PP is a reversible adverse effect that can be observed in patients exposed to biological drugs, mainly anti-TNFα.

Experimental Methods for the Immunological Characterization of Paradoxical Psoriasis Reactions Induced by TNF-α Biologics

Immunomodulation with anti-TNFα biologics is highly effective in the treatment of various immune-mediated inflammatory diseases, even though 2-5% of patients treated can develop paradoxical psoriasiform skin lesions. We recently analyzed three patients affected by severe hidradenite suppurativa (HS), and who developed paradoxical psoriasiform reactions following treatment with the TNF-α blockers. Psoriasiform skin reactions showed immunological and immunohistochemical features common to acute psoriasis, characterized by cellular players of innate immunity, such as plasmacytoid dendritic cells (pDC), neutrophils, mast cells, macrophages, and monocytes. In addition, IFN-β and IFN-α2a, two type I IFNs typical of early psoriasis, were highly expressed in paradoxical skin reactions. Concomitantly, the lymphotoxin (LT)-α and LT-β were overproduced. Detection of innate immunity cells was carried out on skin sections from HS patients, by immunohistochemistry (IHC) by using antibodies (Abs) against markers identifying specific leukocyte subpopulations. Anti-BDCA2, anti-CD15, anti-CD117, anti-CD68, anti-CD11c, and anti-CD3 Abs were employed to detect pDC, neutrophils, mast cells, macrophages, monocytes/dendritic cells, and T lymphocytes, respectively. In parallel, skin expression of the innate immunity soluble mediators IL-36γ, IFN-β, IFN-κ, LT-α and LT-β was also evaluated by IHC by using specific Abs. In this chapter, we describe the methods and protocols to detect the in situ expression and localization of innate immunity molecules and leukocyte subpopulations in skin lesions where inflammatory and psoriasiform reactions are evoked by anti-TNF- α biological therapy.

Psoriasis Induced by Biological Therapy

OBJECTIVE

To describe a multicentre case series of new onset or worsening of psoriasis in patients treated with biological drugs.

MATERIAL AND METHODS

Descriptive study. We reviewed the clinical history of patients with chronic inflammatory disease (CID) treated with biological drugs, who developed new onset or worsening of psoriasis during the follow-up period.

RESULTS

Twenty-six cases of paradoxical psoriasis (PP) were recorded. Ninety-three percent of the patients were treated with anti-TNFα and adalimumab was responsible for 50% of the cases. Only 5 patients had a personal history of psoriasis. The biological drug was discontinued in 13 patients. Lesion recurrence was more frequent when another anti-TNFα was reintroduced.

CONCLUSIONS

The PP is a reversible adverse effect that can be observed in patients exposed to biological drugs, mainly anti-TNFα.

Psoriasis and Inflammatory Bowel Disease

BACKGROUND

Inflammatory bowel disease (IBD) and psoriasis (PS) are associated conditions. The reason for this association lies in the sharing of predisposition genes and common immunological mechanisms.

SUMMARY

This review will focus on the interplay between IBD and PS, with details on prevalence and phenotype of PS in IBD, genetics, pathogenetic pathways, and therapy. Key Messages: Microbiome seems relevant in both conditions: a reduction of beneficial bacteria has been observed. IBD and PS have in common some comorbidities like cardiovascular disease, similar risk of cancer and psychiatric problems. Many biological therapies such as anti-tumour necrosis factor (TNF) and anti-interleukin 23 are effective in both conditions, underlining the common immunological mechanisms. Paradoxical PS has been mainly observed after anti-TNF therapies, but preliminary reports show that it can also occur with other biologics. Genetic predisposition to this phenomenon has been reported.