Epidemiology of Itch

Excerpt

While it is often stated that pruritus is the most frequent symptom in dermatology and that it may also occur in internal, neurological, and psychiatric/somatoform diseases as well as that it may be drug-induced, there are surprisingly few studies about the prevalence or incidence of pruritus in particular diseases or patient populations. The situation is made worse by the following:

1. Many patients with acute pruritus but also with chronic pruritus do not present to a physician (Weisshaar et al. 2003; Matterne et al. 2009). This may be the result, for instance, of how the local health system is organized or how access to specialists is regulated (the question of whether a patient can see a specialist directly or only by referral). This explains the need for population-based studies on prevalence and incidence of chronic pruritus.

2. The symptom “pruritus” often receives only minor attention in non-dermatological specialties and is often not considered a variable worth assessing (Weisshaar et al. 2003).

3. The findings of studies on pruritus are often difficult to compare or interpret due to the fact that parameters are not operationalized in a consistent manner (e.g., lack of unanimously accepted definition and classification of pruritus). Clinical studies often use outcome measures that are not clearly defined. For instance, it is important to distinguish between the point (Are you currently suffering from…), period (During the last 12 months have you suffered from…), and lifetime (Have you ever in your life suffered from…) prevalence and clearly communicate the particular kind of prevalence estimate that was measured in a publication.

4. The symptom whether acute or chronic may fluctuate; e.g., it may not occur daily. The most recent classification provided by International Forum for the Study of Itch (IFSI) appears the most comprehensive so far but is far from being perfect.