A raised lump under the ankle should be considered to be caused by a variety of conditions. Firstly, it may be a dermatofibroma, the exact cause of which is unknown and may be related to insect bites and trauma. The second thing to consider is the possibility of common warts, mainly caused by human papilloma virus infection, triggering factors include immune deficiency, local trauma and certain systemic diseases, such as diabetes, malignant tumors, etc. Once again, nodular itchy rash should be considered as a possible cause, which may be related to mosquito, bedbug or other insect bites as well as endocrine disorders and gastrointestinal disorders. In addition, seborrheic keratosis should also be considered as a possible cause of seborrheic keratosis, which is mainly related to genetic factors and skin aging. Predisposing factors include viral infections, ultraviolet radiation, malignant tumors, and the use of certain drugs such as vincristine and adalimumab.