1) Abrasive 2) Acrid 3) Annoying 4) Bothersome 5) Disagreeable 6) Galling 7) Harsh 8) Infuriating 9) Irksome 10) Irritant 11) Irritative 12) Itchy 13) Maddening 14) Nettlesome 15) Pesky 16) Pestering 17) Pesty 18) Plaguy 19) Riling 20) Rough 21) Stimulative 22) Troublesome 23) Uncomfortable 24) Vexatious 1) Annoying 2) Bothersome 3) Causing irritation 4) Causing physical discomfort 5) Disagreeable 6) Distressing 7) Galling 8) Getting at 9) Harassing 10) Irksome 11) Nettlesome 12) Niggling 13) Pesky 14) Pestering 15) Pestiferous 16) Plaguey 17) Plaguy 18) Teasing 19) They can be very painful 20) Troublesome 
• (p. pr. & vb. n.) of Irritate
[adj] - (used of physical stimuli) serving to stimulate or excite 2. [adj] - causing physical discomfort
irritative adjective (used of physical stimuli) serving to stimulate or excite; `an irritative agent`
causing irritation; annoying; provoking: irritating questions.