12-year-old girl on the back of the bump is thin stripes and itchy, considering the insect bite dermatitis or artificial urticaria. Mainly by mosquito bites, mosquitoes secrete some secretions into the human body in the immune response, will appear in the bite site stripes or granular bumps and itchy symptoms, at this time can be applied locally dandelephene ointment or glycerite lotion to stop itching, if necessary, oral antiallergic drugs accordingly. Artificial urticaria is also called skin scratching. Manifested as skin friction, scratches, scratching or pressure after the appearance of line-like protrusions and the surrounding normal skin with clear boundaries between the most important drugs caused by allergies, such as cetirizine or loratadine. 12-year-old girl back bumps are thin stripes, but also itchy, there may also be other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment, the above medication as prescribed by the doctor.