A study published in “The Journal of Pain” depicted that pretherapy with local anesthetic EMLA cream seems to be a good therapy choice to lower the pain linked with 8% capsaicin application to treat neuropathic pain syndromes. J.D. Christensen et al. undertook this study to explore the effects of local analgesia on capsaicin-induced desensitization.

In the first session, the two skin areas in each forearm of 24 healthy participants were randomly assigned to the two-hour pretherapy with EMLA/placebo cream. After pretherapy, 8% capsaicin patches were applied for three hours in one placebo and one EMLA pretreated area, procuring the following four areas: (i) Capsaicin+EMLA, (ii) Capsaicin+Placebo, (iii) EMLA alone, and (iv) Placebo.

The pain intensity scores were evaluated during the three-hour application of capsaicin. After removing capsaicin, estimation of warmth detection, microvascular reactivity, and heat pain sensitivity was done. After 24 hours, in the second session, repetitions of all the tests were done followed by histamine application in each area to assess neurogenic flare and itch intensity.

EMLA substantially declined the capsaicin-induced pain in comparison with placebo and elevated the capsaicin-stimulated rise in superficial blood perfusion instantly following the three-hour capsaicin application. Regardless of the pretherapy, capsaicin stimulated heat hyperalgesia promptly after the application. The heat pain sensitivity was found to be normalized after 24 hours of application. However, the warmth detection threshold was considerably elevated.

Capsaicin tended to lower the itch intensity and remarkably minimized the neurogenic flare stimulated by histamine when compared to EMLA alone. Pre-therapy with topical analgesic cream appears to minimize application site pain without interfering with the 8% topical capsaicin-induced desensitization. Also, this study suggests the existence of a synergistic effect of capsaicin and EMLA on neurogenic inflammation. Thus, for alleviating capsaicin-induced pain, pretreatment with a eutectic mixture of lidocaine and prilocaine is effective.