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The Acute Effect of Skin Preheating on Capsaicin‐Induced Central Sensitization in Humans
Author(s) -
Linde Lukas D.,
Srbely John Z.
Publication year - 2019
Publication title -
pain practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 58
eISSN - 1533-2500
pISSN - 1530-7085
DOI - 10.1111/papr.12811
Subject(s) - capsaicin , medicine , sensitization , central sensitization , pharmacology , anesthesia , dermatology , immunology , nociception , receptor
Topical capsaicin is commonly employed to experimentally induce central sensitization ( CS ) in humans. While previous studies have investigated the effect of skin preheating on the sensitizing effect of capsaicin, no studies have compared the synergistic effect of skin preheating on the magnitude of sensitization via topical capsaicin within the first 30 minutes of application. We tested the hypothesis that skin preheating potentiates the sensitizing effect of topical capsaicin by evoking a larger region of secondary hyperalgesia vs. topical capsaicin alone. Methods Twenty young, healthy subjects each received topical capsaicin (Zostrix HP 0.075%) only ( CAP ), topical capsaicin with preheating ( CAP + HEAT ), and topical nonsensitizing placebo cream ( CON ) in a crossover design. Capsaicin and placebo creams were applied to a 50 cm 2 area of the dorsal forearm. The CAP + HEAT session also included a 10‐minute preheating session. Regions of secondary hyperalgesia were assessed using mechanical brush allodynia testing, and skin temperature was assessed via infrared thermography. Outcomes were normalized to baseline and compared at 10, 20, and 30 minutes after cream application. Results The CAP + HEAT session led to a significantly larger area of secondary hyperalgesia compared to the CAP session as measured by brush allodynia ( CON : 0 ± 0 cm; CAP : 2.08 ± 0.45 cm; CAP + HEAT : 3.70 ± 0.46 cm; P < 0.05) and skin temperature ( CON : −2.92% ± 0.03%; CAP : −0.63% ± 0.09%; CAP + HEAT : 2.50% ± 0.11%; ( of baseline) P < 0.05). Conclusion Preheating amplifies the sensitizing effect of topical capsaicin within 30 minutes of application. The heat–capsaicin technique may be employed to assess differing magnitudes of CS induction and enables future studies investigating the development and progression of CS in humans.