Tumor necrosis factor-α inhibitor (TNFi)–induced psoriasis is a paradoxic reaction characterized by the development of a psoriasiform rash that mimics idiopathic psoriasis subtypes both clinically and histologically. Few studies have investigated the histologic features of TNFi-induced psoriasis skin lesions, and most of these are limited by inclusion of few specimens.
We aimed to characterize histologic features of TNFi-induced psoriasis and identify histologic differences between TNFi-induced psoriasis and idiopathic psoriasis.
We characterized 60 biopsy specimens obtained from 47 unique patients at a single tertiary care referral center between 2004 and 2016 who developed TNFi-induced psoriasis, and we compared histologic features to those of 85 biopsy specimens from a control group of 85 patients with idiopathic psoriasis.
The most common histologic reaction pattern in TNFi-induced psoriasis biopsy specimens was psoriasiform (80.0%). Five histologic parameters were significantly different in TNFi-induced psoriasis biopsy specimens compared with idiopathic psoriasis biopsy specimens: at least 3 dermal eosinophils per histologic section, neutrophils in the stratum corneum, neutrophils in the epidermis, papillary plate thinning, and absence of parakeratosis.
Inability to exclude lesion selection bias as a potential reason for some significant histologic differences.
This study supports the idea that histologic differences exist between TNFi-induced psoriasis and idiopathic psoriasis may help distinguish between these conditions, especially for dermal eosinophil counts of 3 or greater.Le texte complet de cet article est disponible en PDF.
Key words : eosinophils, histology, parakeratosis, psoriasis vulgaris, TNF-α inhibitor–induced psoriasis
Abbreviations used : IL, INF, INF-α, pDC, TNF-α, TNFi
| Funding sources: None.
| Disclosure: Dr Fernandez is an investigator for Pfizer, Corbus, Mallinckrodt, and Novartis Pharmaceuticals and receives personal research support from Mallinckrodt and Novartis; honoraria from AbbVie, UCB, Novartis, and Mallinckrodt for consulting and advisory board participation; and honoraria from AbbVie, Novartis, and Mallinckrodt for teaching and speaking. Mr Hu and Drs Billings and Yan have no conflicts of interest to declare.
| IRB approval status: Reviewed and approved by the Cleveland Clinic IRB (approval #13-701).