Erlotinib-induced Rosacea-like Dermatitis.

Skin and skin adnexa toxicities are the most common side effects associated with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and occur in most patients receiving this therapy. The majority of these cutaneous side effects are transient, reversible, and dose dependent. Although these symptoms are in general not severe, they significantly affect quality of life and can have a serious effect on treatment compliance as well as the treatment regimen. The most common early symptoms present as papulopustules on an erythematous base, usually localized in seborrheic areas. This clinical presentation is commonly described as "acneiform", although these adverse reactions have clinical presentations, such as rosacea-like and seborrheic-like dermatitis. In this context, we report a case of a 77-year-old man with a medical history of planocellular lung cancer with ipsilateral pulmonary metastasis and mediastinum infiltration who received erlotinib as a third-line therapy, presenting with centrofacial rosaceiform rash as a side effect associated with the use of EGFR-TKIs. The patient had a negative previous history of rosacea. Therefore, symptoms probably occurred as an adverse reaction due to the oncological therapy. Current terminology of early cutaneous adverse reactions caused by EGFR-TKIs refers to "acneiform" or "papulopustular" lesions, excluding less common side effects such as rosacea-like dermatitis so these symptoms might be overlooked and misdiagnosed. Thus, we would like to emphasize the importance of developing a more accurate classification of terms in order to provide early detection of all possible cutaneous side effects, including less common ones, providing specific and timely treatment, and allowing continuation of drug therapy.