Ferritin-Related Tingling Mechanisms
Low ferritin can be associated with restless legs syndrome (RLS), which commonly presents with uncomfortable leg sensations described as tingling or “pins and needles.” [1]
Clinical Phenotype Supporting Ferritin-Linked Paresthesia
RLS diagnostic features include an urge to move the legs and unpleasant leg sensations that occur at rest and are typically relieved by movement. [2]
Evidence Linking Low Ferritin to RLS Symptoms
RLS clinical practice guidance recommends assessing iron status because low iron stores are associated with RLS and treatment response. [3]
Treatment Thresholds for Iron Supplementation in RLS
In adults with RLS, iron supplementation should be considered when ferritin is low: oral ferrous sulfate is suggested when ferritin is <75 ng/mL (or transferrin saturation <20%). [3]
Quantified Evidence for Iron Improving RLS Symptoms
Oral iron therapy has demonstrated improvement in RLS symptom scores in a randomized, double-blind, placebo-controlled trial in patients with low-normal ferritin. [4]
Distinguishing RLS From Other Causes of Paresthesia
Peripheral neuropathy is a separate cause of paresthesia and should be considered when symptoms do not match the RLS pattern of rest-related onset and relief with movement. [2]
Practical Evaluation Steps for Persistent or Atypical Paresthesia
Iron studies (including ferritin and transferrin saturation) are recommended in the evaluation of clinically significant RLS. [3]
When Low Ferritin Should Not Be Assumed as the Sole Cause
When paresthesia is persistent, progressive, focal, associated with weakness, or not responsive to addressing iron deficiency in the context of RLS features, alternative etiologies such as peripheral neuropathy should be evaluated. [2]