Increased Capsaicin-induced Secondary Hyperalgesia in Patients With Multiple Chemical Sensitivity
Bibliographic record
Abstract
OBJECTIVE: the underlying cause of pathophysiological mechanisms triggering multiple chemical sensitivity (MCS) remains disputed.Recently, alterations in the central nervous system, for example,central sensitization, similar to various chronic pain disorders, have been suggested. Capsaicin is used in experimental pain models to provoke peripheral and central sensitization. In patients with symptoms elicited by odorous chemicals capsaicin-induced secondary hyperalgesia and temporal summation were assessed as markers for abnormal central nociceptive processing together with neurogenic inflammation (flare). METHODS: sixteen patients fulfilling Cullen criteria for MCS and 15 eczema patients with airway symptoms induced by odorous chemicals (EC) were compared with 29 age-matched healthy controls.Participants underwent 2 intradermal injection of capsaicin (3.3 mM and 33 mM). Measurements included pain intensity, flare, pinprick hyperalgesia, temporal summation, and McGill Pain Questionnaire score. RESULTS: no difference was found in the flare area between the groups. The capsaicin-evoked pain intensity was higher in MCS patients compared with controls (P<0.01, 33 mM). The area of secondary hyperalgesia was larger in both the patient groups compared with controls (P<0.05) at both capsaicin concentrations. Temporal summation was increased in MCS patients compared with controls(P<0.01). Further, in patients with comorbidity of fibromyalgia, pain and chronic fatigue, pain continued after end stimulation, and the stimulus response function was enhanced compared with patients without comorbidity, and significant to controls (P<0.05). CONCLUSION: this is the first study to show facilitated pain processing in MCS and EC patients with the most abnormal responses in MCS.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".