Psoriasis is a common immune-mediated disease that affects approximately 2% of the world's population. Most patients require lifelong treatment and many of the current systemic therapies are complicated by significant toxicities or inconvenience when administered long-term. New biological psoriasis therapies have been developed, which are thought to act through targeted molecular pathways, so as to administer them continuously without causing any relevant toxicity. Nevertheless, acute and chronic dermatological adverse effects are frequently observed, but knowledge about them is limited and the potential pathogenic mechanisms have not yet been identified. We present 7 patients from our dermatological department who presented different cutaneous adverse effects (2 erythrodermias, 1 palmoplantar pustulosis, 1 flexural psoriasis, 1 eczema, 1 neutrophilic dermatosis and 1 papular eruption) during treatment with biological drugs (4 patients with efaluzimab, 2 patients with infliximab and 1 patient with etanercept). The use of biological agents is expanding worldwide as new alternative treatments for psoriasis and other chronic inflammatory diseases. The increased use of these treatments has allowed identification of their acute and chronic systemic adverse events. Nevertheless, the dermatological adverse events of these biological drugs are less well known due to few reports about them and lack of information about their pathogenic mechanisms. Exact diagnosis of these cutaneous eruptions is very important in order to decide the need for discontinuation of the biological treatment.