[Pain and pruritus : differences and similarities as revealed by the PainDetect questionnaire parameters]

Development and preliminary validation of the patient-reported Chronic Itch Burden Scale assessing health-related quality of life in chronic pruritus

BACKGROUND

Chronic pruritus (CP) significantly affects patients' health-related quality of life (HRQoL). Very few self-reported HRQoL questionnaires exploring CP have been developed according to international guidelines, thus limiting their use in preauthorization trials.

OBJECTIVES

To develop a self-reported HRQoL questionnaire in patients with CP owing to psoriasis, atopic dermatitis, seborrhoeic dermatitis of the scalp or idiopathic dermatitis, and to explore the preliminary psychometric properties of the questionnaire.

METHODS

The study was performed in France. A conceptual framework was developed based on a structured literature review and expert insight, and was improved using three focus groups involving 19 participants. A 50-item questionnaire was created and tested with 21 participants using cognitive debriefings; 11 items were removed. A cross-sectional study including 251 participants was performed to explore the preliminary psychometric properties of the 39-item questionnaire. Dimensionality was explored using principal component analysis. Cronbach's alpha and correlation coefficients (interitem, item-total score and item-dimension score) were measured. The number of items was reduced through expert consensus.

RESULTS

In the 39-item version, three main dimensions were identified (Cronbach's alpha = 0·94) and all correlation coefficients were > 0·34. Upon review, 13 items were deleted owing to poor quality and six items were deleted by the team, generating a 20-item version. The questionnaire's factorial structure was best reflected with a two-dimension solution, i.e. (i) social and emotional repercussions and (ii) relation to others, fear of judgement.

CONCLUSIONS

The Chronic Itch Burden Scale patient-reported questionnaire explores broad aspects of HRQoL that are relevant for patients with various skin diseases. Its good cross-sectional validity makes it useful for trials and practitioners.

Prevalence of Neuropathic Pain and Related Characteristics in Hidradenitis Suppurativa: A Cross-Sectional Study

BACKGROUND

Pain is a core symptom of hidradenitis suppurativa (HS) and is of complex, multifactorial origin. HS patients frequently report typical neuropathic pain qualities, but its prevalence has been poorly described.

METHODS

In this cross-sectional study, we examine the prevalence of neuropathic pain (NP) component and related pain-characteristics of a hospital-based cohort of patients with symptomatic HS. We administered the pain-DETECT tool (PDQ), a validated screening tool for NP, collecting clinical and patient-reported data on pain, pruritus and pain-management. We obtained 110 complete datasets from symptomatic HS patients (49.1% females; Hurley I (27.3%])-II (45.5%)-III (27.3%)). According to the PDQ tool, 30% of patients were classified with a high probability (>90%) of neuropathic pain (LNP). LNP status was significantly associated with increased pain severity, disease activity, pruritus intensity and use of pain medication. Regression analysis showed a significant impact of the PDQ score on patient-reported outcomes, including pain severity and the dimensions of activity and affective pain interference. HS patients may present a mixed chronic pain phenotype with a neuropathic component, thus requiring additional pain-assessments. A multi-modal approach to pain management, in combination with disease-specific treatment, should be implemented in future interventional studies.

The painDETECT project - far more than a screening tool on neuropathic pain

Background and objectives The painDETECT questionnaire (PD-Q), a simple and reliable screening questionnaire of neuropathic pain, was developed in 2004 in cooperation with the German Research Network on Neuropathic Pain. The initial aim was to implement quality management and to improve the situation of neuropathic pain (NeP) patients in Germany. The PD-Q proved immediately successful and was translated into and validated in multiple languages. Subsequently a comprehensive electronic system (PD) comprising various validated questionnaires with regard to pain typical comorbidities, such as function, sleep, mood or anxiety, was implemented Germany wide. We aimed to provide a comprehensive overview about the development and validation as well as the application of the PD-Q in various clinical conditions. Methods This overview is based on a literature search on English full-text papers using the term 'painDETECT' in Medline and PubMed covering the time period from 2006 to September 2015, amended with further publications cited in the retrieved publications or provided by the questionnaire developers. Results PD-Q as screening tool for NeP described in patients with lower back pain (8 studies), rheumatoid arthritis and osteoarthritis (10), thoracotomy (2 studies), tumor diseases (4 studies), fibromyalgia (4 studies), diverse musculoskeletal conditions (12 studies) and diverse other conditions (10 studies). In addition, the PD-Q was used in 9 studies that investigated the effect of drugs for the treatment of patients with a NeP component. Conclusion To date more than 300,000 patients were assessed, providing the basis for one of the world's largest datasets for chronic pain. Among others the extensive pool of PD-Q data triggered the idea of subgrouping patients on the basis of their individual sensory profiles which might in the future lead to a stratified treatment approach and ultimately to personalized therapy. Started as a healthcare utilization project in Germany, the PD-Q is nowadays used for clinical and research purposes around the world.

How to Psychologically Minimize Scratching Impulses

Research in recent years, especially in the analgesic field, has intensively studied the placebo effect and its mechanisms. It has been shown that physical complaints can be efficiently reduced via learning and cognitive processes (conditioning and expectancies). However, despite evidence demonstrating a large variety of physiological similarities between pain and itch, the possible transfer of the analgesic placebo model to itch has not yet been widely discussed in research. This review therefore aims at highlighting potential transfers of placebo mechanisms to itch processes by demonstrating the therapeutic issues in pharmacological treatments for pruritus on a physiological basis and by discussing the impact of psychological mechanisms and psychological factors influencing itch sensations.