Disclosed is a pyrazolopyrimidine derivative represented by formula (I), a pharmaceutically acceptable salt thereof or the like, which is useful as a prophylactic and/or therapeutic agent for skin diseases.(In the formula, R1 represents -NR1aR1b (wherein R1a and R1b may be the same or different and each represents a hydrogen atom, an aralkyl group or the like) or the like； R2 represents a group represented by formula (Ya) (wherein k and m each represents an integer of 0-2； n represents an integer of 0-4； L represents a single bond or the like； R5 represents a halogen or the like； R6 represents an aryl or the like； X represents CR8 (wherein R8 represents a hydrogen atom or the like) or the like； and R7 represents a hydrogen atom or the like) or the like； R3 represents -SO2R13a (wherein R13a represents a lower alkoxy, -NR13dC(=O)R13e (wherein R13d represents a hydrogen atom or the like, and R13e represents a lower alkyl or the like) or the like) or the like； and R4 represents a hydrogen atom or the like.)
