Neutrophilic dermatoses
Neutrophilic dermatoses (ND) comprise a heterogeneous group of non-infectious skin diseases characterized by a diffuse epidermal and/or dermal infiltrate consisting of polymorphonuclear neutrophilic inflammatory cells throughout the different skin layers. Depending on the localization of this infiltrate, patients may present with a variety of skin lesions such as pustules/vesiculopustules (epidermal infiltrate), plaques or papules (dermal infiltration), nodules or ulcerations (deep dermal/subcutaneous infiltrate) and also with possible systemic symptoms, such as leucocytosis, arthralgias, myalgia, and malaise. Based on the clinical picture of cutaneous lesions and further systemic symptoms the patients can be subdivided into different entities. These include Sweet’s syndrome (SS), pyoderma gangrenosum (PG), rheumatoid neutrophilic dermatitis, bowel-associated dermatosis-arthritis syndrome, subcorneal pustular dermatosis (Sneddon Wilkinson), acute generalized exanthematous pustulosis (AGEP), acrodermatitis continua of Hallopeau (ACH), palmoplantare pustuloses (PPP), pustular bacterid (PB), neutrophilic eccrine hidradenitis, and Behçet’s disease. The pathogenesis is still not fully elucidated but it has been hypothesized that it is associated with immunological dysfunctions, with abnormal cytokine signalling, causing an uncontrolled recruitment of neutrophilic cells. ND can be triggered by underlying systemic inflammatory diseases, malignancies, haematological disorders and/or medication use. Diagnostic procedures include detailed physical examination, laboratory tests, and histopathological assessments. The therapeutic management of ND is mainly based on systemic steroids in acute cases and immunosuppressive or immunomodulatory drugs in chronic forms. Underlying systemic conditions have to be diagnosed and treated as early as possible to avoid complications.