What is the best course of action for a patient experiencing itching symptoms while taking levothyroxine (T4) with elevated Thyroid-Stimulating Hormone (TSH) suppression?

From the Guidelines

The patient's levothyroxine dose should be adjusted to alleviate itching symptoms and achieve normal thyroid hormone levels, as the current suppressed TSH level and elevated T4 and T3 levels may indicate hyperthyroidism, which can cause skin symptoms 1. The patient is experiencing itching while taking levothyroxine with a TSH level of 0.02, which is below the normal range, and elevated FREE T4 and free T3 levels, indicating potential hyperthyroidism.

• Itching can be a sign of thyroid hormone excess, and adjusting the levothyroxine dose may help alleviate this symptom.
• The patient's doctor may temporarily reduce the dose or switch to a different brand or formulation of levothyroxine that doesn't contain fillers or dyes that could be causing an allergic reaction.
• In the meantime, the patient can manage itching symptoms with cool compresses, fragrance-free moisturizers, and over-the-counter antihistamines like cetirizine or diphenhydramine.
• The goal is to achieve normal thyroid hormone levels while eliminating the itching side effect, as proper thyroid function is essential for overall health, and the current TSH suppression may not be necessary for all patients, especially those without thyroid cancer or nodules 1.
• However, the most recent and highest quality study is not directly applicable to this specific scenario, but the general principle of adjusting the levothyroxine dose to achieve normal thyroid hormone levels and alleviate symptoms is still relevant 1.

From the FDA Drug Label

Adverse Reactions • Instruct patients to notify their healthcare provider if they experience any of the following symptoms: ... hives or skin rash, or any other unusual medical event.

The patient is experiencing itching, which could be related to an adverse reaction to levothyroxine.

• The patient should notify their healthcare provider about the itching symptoms.
• The healthcare provider may need to adjust the dose or monitor the patient for any other unusual medical events. 2

From the Research

Patient's Condition

The patient is a 64-year-old female with a TSH level of 0.02, FREE T4 of 25.6, and free T3 of 6.7, and is experiencing itching symptoms while on levothyroxine 100mcg.

Thyroid Hormone Levels

• The patient's TSH level is suppressed, indicating that the levothyroxine dose may be too high 3, 4.
• The FREE T4 level is elevated, which is consistent with the suppressed TSH level 3, 4.
• The free T3 level is within the normal range, but may not be optimal for the patient's symptoms 4, 5.

Itching Symptoms

• Itching can be a symptom of thyroid hormone imbalance, particularly if the patient is experiencing thyrotoxicosis or hypothyroidism 6, 7.
• The patient's itching symptoms may be related to the elevated FREE T4 level and suppressed TSH level 3, 4.

Treatment Considerations

• The patient's levothyroxine dose may need to be adjusted to achieve optimal thyroid hormone levels and alleviate symptoms 3, 4, 5.
• The patient's free T3 level may need to be monitored and adjusted separately to ensure optimal levels 4, 5.
• Other factors that may be contributing to the patient's itching symptoms, such as skin conditions or other medications, should be investigated and addressed 6, 7.

Reference Intervals

• The patient's thyroid hormone levels should be compared to established reference intervals to determine if they are within the normal range 7.
• The reference intervals for thyroid hormone levels may vary depending on the laboratory and assay used, and should be taken into consideration when interpreting the patient's results 6, 7.