Psoriasis: Rediscovering the meaning of the name.

Abstract

Psoriasis is probably as old as humankind. However, over the centuries, the disease has been called by many different names (e.g. lepra, impetigo, psora, alphos) and the first firm position in favour of defining the condition with the name as we know it today dates from 1840.1 And just like its nomenclature, similar confusion has surrounded other aspects of the disease, leading to a myriad of false myths. It was, for instance, thought to be contagious: in the Old Testament, in which many cases of ‘leprosy’ are now believed to be psoriasis, Gehazi was cursed by Elisha to be clung by the ‘lepra’ of the soldier Naaman. When Gehazi left the prophet, he was ‘as white as snow’, infected by a disease that was most likely psoriasis.1 It was not until the end of the 20th century that the concept of psoriasis as a primary disorder of keratinocytes was replaced by that of psoriasis as an immune-mediated and inflammatory systemic disease. In fact, before then, it was considered almost exclusively a skin condition, with ‘arthropathy as the only recognized non-cutaneous manifestation of the disease’.2 But the most surprising misconception, especially considering that the Greek word ‘psora’ means itch, is that no mention of pruritus as a symptom had been made in the first editions of many dermatology textbooks. Moreover, our ancient masters taught us that it was a non-itchy dermatosis, to help differentiate psoriasis from eczema. Dermatologists appear to have been reluctant to associate psoriasis with pruritus: a PubMed research with the keywords “psoriasis” and “itch” returned an average of only nine articles per year in the period from 1951 to 2009. An increase in attention can be observed between 2010 and 2019, with an average of 62 articles per year, but an explosion of interest was evident only in the last 3 years, with more than 135 articles annually. This is an undoubted sign that we have finally started to listen to our patients' complaints, but this delay in recognizing the significance of such a symptom is quite unbelievable, considering that itch was reported in 64%–98% of patients3 and many of them describe it as the most important, the most frequent and the most bothersome subjective sensation.4 Within this growing attention to pruritus in psoriasis, most of the papers refer only to plaque psoriasis, whereas the multicenter study presented by Jaworecka et al.4 in this issue of the Journal, goes one step further, trying to describe the specific characteristics of this long neglected symptom in different clinical variants of the disease, focusing on the duration, localisation and frequency of itching. Moreover, in a patient-oriented approach, the enrolled individuals were also asked to describe their sensations of pruritus. The authors found that pruritus is almost always observable in every clinical variant of psoriasis, with a lifetime prevalence ranging from 86.1% to 100% in nummular psoriasis, scalp psoriasis and generalized pustular psoriasis (GPP). Psoriasis severity correlated with pruritus intensity only in scalp psoriasis, palmoplantar pustular psoriasis and GPP, while this correlation was surprisingly not observed in plaque, guttate, inverse and erythrodermic psoriasis. The most common terms used to describe pruritus in all investigated subtypes of psoriasis were burning, pinching and tingling. In conclusion, the study provides many interesting clues on an issue that is still far from being clarified, since the collected data show that the sensation of itch is very subjective and hard to describe universally even in the same subtype. Although the first documented use of the term ‘psoriasis’ dates back to Classical times [Galen of Pergamon (ca. A.D. 133–200)1], almost two millennia had to pass before it assumed its present appellation. What is more, it is still unclear why this term was finally chosen over the others, considering that itch was not historically associated with the disease. George Orwell once argued that ‘to see what is in front of one's nose needs a constant struggle’; better late than never, we are now perfectly conscious that the etymology and symptom coincide. Psoriasis must, indeed, be considered an itchy dermatosis and as Erasmus Wilson said when talking about the need to adopt the term psoriasis, ‘the change is simple, the reasons for it important’.1 We can do no better than to continue our investigation on this topic, to personalize treatment and better manage what we now know to be the most troublesome symptom of this condition. None. The authors have no conflict of interest to disclose. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.