Historically, drugs available for treating atopic dermatitis (AD) have been limited to topical corticosteroids (TCS) and topical calcineurin inhibitors (TCI), with systemic immunosuppressants and phototherapy reserved for severe AD. Despite their efficacy, with long term use, these agents have associated safety concerns and limitations. More targeted options with fewer systemic and cutaneous side effects are needed for treating atopic dermatitis. Phosphodiesterase 4 is involved in the regulation of proinflammatory cytokines via the degradation of cAMP. Phosphodiesterase 4 (PDE4) activity is increased in the inflammatory cells of patients with AD, leading to increased production of proinflammatory cytokines and chemokines. Targeting PDE4 reduces the production of these proinflammatory mediators in AD. Both topical and oral PDE4 inhibitors have a favorable safety profile. Crisaborole 2% ointment, a topical PDE4, is now FDA-approved for children >2yrs of age and adults in the treatment of AD. Crisaborole 2% ointment shows early and sustained improvement in disease severity and pruritus/ other AD symptoms, with burning/stinging upon application as the only related adverse event. Other PDE4 inhibitors are currently in trials with promising efficacy and safety.

从历史上看，可用于治疗特应性皮炎（AD）的药物仅限于局部皮质类固醇（TCS）和局部钙调神经磷酸酶抑制剂（TCI），而全身性免疫抑制剂和光疗则保留用于严重AD。尽管具有功效，但长期使用这些药物仍存在相关的安全性问题和局限性。治疗特应性皮炎需要更多的靶向选择，而全身和皮肤的副作用更少。磷酸二酯酶4通过cAMP的降解参与促炎细胞因子的调节。磷酸二酯酶4（PDE4）活性在AD患者的炎性细胞中增加，导致促炎性细胞因子和趋化因子的产生增加。靶向PDE4可减少AD中这些促炎介质的产生。局部和口服PDE4抑制剂均具有良好的安全性。FDA批准了2％的Crisaborole软膏（一种局部PDE4）用于治疗2岁以上的儿童和成人，用于AD治疗。2％的Crisaborole软膏显示出疾病严重程度和瘙痒/其他AD症状的早期和持续改善，应用时灼痛/刺痛是唯一相关的不良事件。其他PDE4抑制剂目前正在试验中，它们的疗效和安全性令人鼓舞。