"i have had a overactive thyroid disorder for 3 years which i had radiotherepy treatment for. then it went underactive. so 10 years on i have been on levothyroxine &amp; regular blood tests. this is now for life. i have every symptom going for thyroid disorder,including raging acne. hard lumps with red tops that stay for months at s time. its hard not to try squeezing them ( even though we know we shouldnt) but thats mainly how it spreads. with the thyroid disorder,a lot of symptoms are hormonal. i thought at age 34 i shouldnt still be struggling with acne. so my doctor tried me on many creams,tablets ect. until he gave me doxycycline. 100mg once a day. i must say these are brill. just be patient."