Phosphodiesterase 4 (PDE4) is a key enzyme in the regulation of immune responses of inflammatory diseases through degradation of the second messenger, cyclic adenosine 3',5'-monophosphate (cAMP). Apremilast, a selective PDE4 inhibitor, has been shown to reduce the production of pro-inflammatory cytokines by increasing intracellular levels of cAMP and promoting the production of anti-inflammatory cytokines. The efficacy and safety of apremilast in the treatment of psoriasis and psoriatic arthritis has been demonstrated in phase 2 and 3 studies and will be reviewed here. Across all studies, treatment was generally well-tolerated with some mild gastrointestinal complaints that occurred early and resolved over time, resulting in few drop-outs. Meaningful changes in dactylitis and enthesitis were also observed. Routine monitoring is not required given the absence of drug associated physiologic, biochemical, and haematological changes. Apremilast proves to be a new promising systemic therapy for treating psoriatic disease.