I have a hypothyroidism, and was off meds for a couple of years. A few months ago, I tested 15 tsh and my dr started me on 50 mcg levothyroxine. After 8 weeks I retested and my tsh was 7, normal range being below 4. My dr increased my dosage again to 75mcg. Soon after this increase I started noticing hives. Hives cover my torso, thighs, buttocks, and they are large welts, extremely itchy. I thought it was the levothyroxine so I switched to synthroid. This change had no effect. I saw an allergist and did a scratch test with everything coming back negative. I stopped taking meds and subsequently my tsh shot back up to 22. Hives keep getting worse, especially waking up In the morning. I found out I was pregnant and went to see endo, who immediately changed my dosage to 200 mcg synthroid, and no relief from hives. I just switched to 200 mcg tirosint which has no fillers. It's been a week hives are not a severe but still occur. How long until the synthroid is out if my body so I can find a reason for hives? I suffer daily and don't want to take too much Benadryl while pregnant but hives are unbearable.