Targeted treatments and immunotherapies are linked to a variety of dermatologic adverse events (dAEs), which are caused by signaling pathways that were involved in both malignant activity and normal epidermal and dermal homeostatic activities. Skin, oral mucosa, hair, and nails were all affected by dermatological toxicity. The most prevalent dAE is acneiform rash, which occurred in 25–85% of patients who were treated with inhibitors of the epidermal growth factor receptor and mitogen-activated protein kinase. 

Secondary skin cancers, squamous cell carcinoma, and keratoacanthomas, as well as hand-foot skin responses and a maculopapular hypersensitivity-like rash, were the most common side effects of BRAF inhibitors. Nonspecific maculopapular rash, eczema-like or psoriatic lesions, lichenoid dermatitis, xerosis, and pruritus were the most common side effects of immune checkpoint inhibitors (ICIs). Oral mucositis was the most common toxicity related with mammalian target of rapamycin (mTOR) inhibitors, followed by stomatitis associated with multikinase angiogenesis and HER inhibitors, geographic tongue, oral hyperkeratotic lesions, lichenoid responses, and hyperpigmentation. 

Oral lichenoid responses and xerostomia were the common side effects of ICIs. Alopecia is a frequent side effect of targeted medicines and endocrine therapy, albeit the latter was largely underreported. Finally, targeted treatments might cause paronychia and periungual pyogenic granuloma, which were separate from chemotherapy-induced lesions. Mild onycholysis, brittle nails, and a decreased rate of nail development were all possible symptoms. Patients’ quality of life was sometimes severely impacted by targeted medicines and immunotherapies, which had an influence on treatment results.