With the increasing research on lung cancer driver genes, tyrosine kinase inhibitors (TKI) targeting the epidermal growth factor receptor (EGFR) are emerging as an important treatment modality for advanced non-small cell lung cancer (NSCLC). It is currently the most effective molecularly targeted drug for the treatment of advanced NSCLC with EGFR-sensitive mutations. Prominent representatives are erlotinib (Erlotinib), gefitinib (Gefitinib) and erlotinib (Icotinib). Although TKI have shown good efficacy in the treatment of NSCLC, they can also produce some side effects, including rash, nail infection, diarrhea, conjunctivitis, hepatotoxicity, and interstitial pneumonia (Figure 1). In order to maintain TKI therapy for the clinical benefit of patients as long as possible when the situation allows, we need to manage the adverse drug reactions promptly. Today, I would like to discuss the prevention and management of rash, one of the common adverse reactions associated with EGFR TKI, with all patients. Molecularly targeted drug rash is characterized by a scattered or fused acne-like follicular rash, mainly on the trunk, face, neck and scalp. The common order of rash appearance is: head and face → forehead and back → neck and neck → abdomen → groin → perineum, perineum and extremities, with the head and face being the heaviest, and the rash being more dense and large in size, while the extremities are more scattered in distribution. The proper administration of TKI: Within the epidermis, EGFR plays an important role, such as promoting epidermal growth, inhibiting differentiation, preventing UV damage, inhibiting inflammation, and accelerating wound healing. EGFR TKI inhibition of EGFR can affect the proliferation, differentiation, migration, and adhesion of keratinized cells in the basal layer, which will lead to skin toxicity. TKI system exposure will increase after eating, which will further inhibit EGFR, so take TKI 1 hour before meal or 2 hours after meal to prevent rash. 2. Daily skin care: In addition to choosing the right time to take the drug, rash can be prevented by daily skin care (Figure 2). This includes avoiding excessive use of soap and using bathing skin care products whenever possible, avoiding sun exposure, using sunscreen (sunscreen value 30 or higher) and wearing protective clothing when outdoors, and using non-alcoholic moisturizing creams for regular skin care since alcohol preparations can cause dry skin. 3, drug prevention: According to a pan-Canadian EGFR-TKI-related rash study (phase III study) at the 2014 ASCO meeting [1], prophylactic use of minocycline significantly reduced the incidence of severe (grade 3) rash, significantly delayed the time to rash, and improved patient compliance with treatment. Minocycline, also known as dimethylaminotetracycline or memantine, is a broad-spectrum antibacterial tetracycline antibiotic. It can bind to tRNA to achieve the effect of bacterial inhibition. Minocycline has a broader antibacterial spectrum than similar drugs with antibacterial activity. While dermatology is commonly used to treat patients with acne, the primary reason for rash prevention with minocycline is to reduce the inflammatory response in the body, not to be antibacterial. Rash prevention begins on the first day of TKI with 100 mg of oral minocycline twice a day for 4 weeks; thereafter, it is observed every 4 weeks until a rash develops and is treated accordingly. If the patient does not tolerate the standard dose, the dose can be adjusted under medical supervision. Its incidence of severe (grade 3) rash can be reduced from 34.1% to 9.5%, which greatly reduces the incidence of rash. In addition, prophylactic use of minocycline significantly delayed the onset of rash from 12 days to 17.4 days. In addition, the dose of TKI drugs needs to be adjusted according to the occurrence of rash, and even the use of TKI needs to be suspended if the reaction is severe (must be determined by the competent doctor). 4. Treatment of rash In the Pan-Canadian EGFR-TKI-associated rash study, the investigators classified the rash into 4 grades according to its severity and used different treatments for each grade. Regardless of the grade of rash, topical 2% clindamycin and 1% hydrocortisone ointment can be used twice a day after its appearance. Severe cases require temporary discontinuation of TKI (always determined by a competent physician) and the addition of minocycline and topical 2% clindamycin, 0.1% tretinoin ointment for crusted breakouts. Since TKI is a specific molecular targeting drug that acts only on tumor cells and causes less damage to surrounding normal tissues and cells, it has its unique side effects as widespread drug follicular rash in the skin mucosa of the whole body, although it does not have the toxic side effects reactions of general chemotherapy drugs, such as nausea, vomiting and hair loss. We hope that by learning and understanding the adverse effects of TKI, we can minimize the side effects caused by the drug, avoid the infection of skin rash and reduce the discomfort of patients, so that patients can be treated in a comfortable environment as much as possible and maximize their quality of life and prolong their survival.