Acupuncture for the Treatment of Itch: Literature Review and Future Perspectives

Chronic itch is a medical condition that affects millions of people worldwide, causing not only physical discomfort but also significant impacts on patients' quality of life. When itching persists for more than six weeks, it is considered chronic and can be as debilitating as chronic pain. Population studies show that between 8% and 13% of people may suffer from this problem, although it is often underestimated by health professionals. Itching can arise from various causes, including skin diseases such as atopic dermatitis and psoriasis, as well as systemic problems such as renal, hepatic, or neurological disorders.

Given the multiple side effects of conventional treatments such as topical corticosteroids and systemic antihistamines, researchers have sought non-pharmacological therapeutic alternatives, including acupuncture.

This study consisted of a narrative review of the existing scientific literature on the use of acupuncture in the treatment of itch. The researchers analyzed various types of studies, including controlled clinical trials, observational studies, and previous systematic reviews, with the objective of assessing the efficacy of acupuncture for the relief of chronic itch. The methodology involved a comprehensive search of the medical literature to identify all relevant studies that investigated the application of acupuncture in different types of itch, from those related to dermatologic diseases to itching associated with renal problems and other systemic conditions. The authors also examined the possible mechanisms of action of acupuncture in the nervous system and how this centuries-old technique could interfere with the neural circuits responsible for transmitting the sensation of itch.

The results of the review showed preliminary evidence that acupuncture may have some benefit in the treatment of itch, but the conclusions are limited by the low quality of the available studies. A 2015 systematic review found a statistically significant difference in itch intensity, with a mean reduction of approximately 19 points on a 0–100 scale. However, this analysis included only three controlled clinical trials, totaling only 70 patients, with one of the studies having an extremely small sample of only 10 people. The studies primarily analyzed patients with atopic dermatitis and uremic itch (related to renal problems).

The most commonly used acupuncture point was Quchi (LI-11), located at the elbow, which according to traditional Chinese medicine has properties to disperse pathogenic factors of the skin. As for mechanisms of action, the researchers identified several explanatory theories, including modulation of histamine release, activation of opioid receptors, and influence on brain regions related to motivation to scratch, as demonstrated in functional MRI studies.

For patients suffering from chronic itch, these findings suggest that acupuncture may represent an interesting complementary therapeutic option, especially considering the favorable safety profile of the technique compared to conventional pharmacologic treatments. Acupuncture has practically no significant side effects, unlike topical corticosteroids that can cause skin atrophy, or antihistamines and other systemic medications that can cause drowsiness, swelling, gastrointestinal problems, and even hepatic toxicity. For health professionals, the results indicate that acupuncture can be considered as part of an integrated therapeutic approach, especially in cases where conventional treatments have not provided adequate relief or have caused unacceptable adverse effects. However, it is essential that physicians understand the limitations of current evidence and discuss honestly with their patients that, although promising, the efficacy of acupuncture for itch is not yet definitively established.

The main limitations of this review include the scarcity of well-designed studies with adequate patient samples. Many of the studies analyzed had important methodological problems, such as lack of clear description of randomization methods, absence of appropriate control groups, and poorly standardized outcome measures. In addition, there is great heterogeneity among studies regarding the acupuncture points used, treatment protocols, and methods for assessing itch. Some studies used the traditional visual analog scale, while others employed multidimensional instruments that assess not only the intensity of itch but also its impact on sleep, anxiety, and quality of life.

This lack of standardization makes comparisons between studies difficult and prevents more robust analyses of pooled data. The authors conclude that, although the preliminary results are encouraging, larger and better-designed controlled clinical trials are needed, ideally comparing acupuncture not only with placebo but also with established pharmacologic treatments, to definitively determine the role of acupuncture in the therapeutic arsenal against chronic itch.