Behcet's-like disease induced by secukinumab in a patient with psoriasis: a case report and literature review.

Purpose: The incidence of cutaneous paradoxical reactions associated with IL-17 inhibitors has gained attention in recent literature. Our report aims to investigate the characteristics of one rare paradoxical reaction, presenting as Behcet's disease.Methods: We reported one case of Behcet's-like disease induced by secukinumab in a patient with psoriasis. This patient, a young woman with a long history of psoriasis, showed significant improvement in her psoriatic condition after receiving four doses of secukinumab. Unexpectedly, she developed symptoms such as high fever, painful oral and genital ulcers, facial maculopapules, and erythema nodosum-like lesions on her lower limbs. Despite neutrophilia, there was no evidence of infection found in her laboratory tests. Histological analysis of a skin biopsy highlighted subcutaneous panniculitis and a mixed inflammatory cell infiltrate in the dermis. The patient was consequently diagnosed with secukinumab-induced Behcet's-like disease. Additionally, we have reviewed nine other documented cases of Behcet's-like disease triggered by IL-17 inhibitors.Results: This group showed no significant gender preference, suffering from conditions such as psoriasis, ankylosing spondylitis, and hidradenitis suppurativa. Oral and genital ulcers were prevalent among the paradoxical reactions noted. Marked improvement was observed in all patients upon discontinuation of the IL-17 inhibitors.Conclusions: Our report serves to alert physicians to this uncommon but significant paradoxical effect that may arise with anti-IL-17 treatment.

Pigmented purpura dermatosis-like mycosis fungoides: four case reports and a review of published cases.

Mycosis fungoides (MF) is the most prevalent type of cutaneous T-cell lymphoma and is generally characterized by multiple patches or plaques with fine scales. One of its variants manifests with multiple purpuric eruptions, mimicking benign pigmented purpuric dermatosis (PPD). To investigate clinicopathological features of PPD-like MF patients. We report four PPD-like MF cases and summarize the clinicopathological features described in reports of nine PPD-like MF cases published in the past 20 years. Compared with benign PPD, petechial lesions in PPD-like MF are more generalized, persistent, and resistant to conventional steroid treatment. Histologically, a superficial dermal band-like infiltrate of atypical lymphocytes with epidermotropism seems to be the most common feature of PPD-like MF. A lymphoid phenotype of CD4+ CD7- T cells and a monoclonal T-cell profile, demonstrated by T-cell receptor gene arrangement analysis, favour a diagnosis of PPD-like MF. Although the exact relationship between PPD and PPD-like MF remains unclear, our study has attached importance to the differential diagnosis of the two diseases in cases of overlooked MF variants. If persistent or generalized purpuric lesions are present, PPD-like MF should be taken into consideration. A thorough physical examination combined with pathological findings may lead to a correct diagnosis.