A skin sensing system for a drug delivery device includes a control unit and a skin sensor comprising one or more electrodes. The skin sensor may be configured to store a threshold value associated with skin sensing, receive one or more sensed signal values from the one or more electrodes, compare the one or more sensed signal values with the threshold value, and based on the comparison, transmit a resultant signal to the control unit. The resultant signal is used by the control unit to determine whether a skin surface of a user is substantially proximate to the skin sensor upon receiving the resultant signal. A drug delivery device (50) for sensing contact with the skin includes the skin sensing system. When the skin sensor senses that the drug delivery device is in contact with a patient's skin surface, drug delivery from the device may be permitted.
