The present invention relates to a pen for the treatment of dermatological disorders, such as warts and the like, by means of a coolant. The pen includes a distal part having a holder for the storage of a coolant and a proximal part with an applicator for the administration of the coolant to the dermatological surface for treatment. These parts extend axially and are in coolant communication by means of a coolant passage in the proximal part, in which a valve body is provided for closing off and/or opening the passage. The passage is provided with at least one bypass for the coolant. In addition, the invention relates to a method for the administration of the pen.