PRIME Journal Vol. 11 Issue 4

ROSACEA AND ITS SYSTEMIC CO-MORBIDITIES AND ASSOCIATIONS FirasAl-Niaimi,MD and WassimTaktouk,MD discuss the links between rosacea andother systemswithin thebody, including thegut, cardiovascular diseases and the respiratorysystem ABSTRACT Rosacea is a common inflammatory skin disease typically prevalent among fair- skinned individuals and manifesting with centrofacial erythema and episodes of inflammatory lesions in the absence of comedones. Over the last few years, there has been increasing evidence linking rosacea to other systems in the body and some even posed the question of whether rosacea is part of a systemic disorder rather than just skin-limited. Perhaps the commonest known link is with certain dietary triggers such as alcohol and spicy food but it is now known that gut health plays a role in certain inflammatory skin diseases, with rosacea being one of them. The term ‘gut dysbiosis’ is referred to alteration in the gut microbiome composition, which has been linked to worsening of rosacea. Similarly, a link was found between inflammatory bowel disease and bacterial overgrowth in the gut and rosacea. The relationship between rosacea and other organ systems is not limited to the gastrointestinal system alone. Case-control and observational studies have shown a link with cardiovascular diseases, notably cardiometabolic with chronic inflammation being a common feature in both. Other links were with certain auto-immune diseases as well as the respiratory and neuropsychiatric systems. This article explores these links and poses the question of whether rosacea is skin-limited or part of a systemic entity. R OSACEA IS A COMMON inflammatory skin condition with a high prevalence among the western population and, in particular, white female women aged between 20–45 years 1 . While the signs and symptoms predominantly appear on the central part of the face (mid- forehead, nose, and medial cheeks), there has been increasing interest and emerging evidence linking it with other organ systems and co-morbidities beyond simply just the skin. The question one could pose is whether rosacea is a cutaneous-limited disease or one with systemic involvement or perhaps a manifestation of a wider systemic inflammation? At the present time, the exact pathophysiology of rosacea remains unclear though it involves an interplay between an aberrant neurovascular signalling and a dysregulation of the immune system, in particular the innate system 2 . High levels of cathelicidins (anti-microbial peptides expressed by leukocytes and epithelial cells) KEYWORDS Cardiovascular, Diet, Gastrointestinal, Respiratory, Rosacea The question one could pose is whether rosacea is a cutaneous-limited disease or onewith systemic involvement or perhaps a manifestation of awider systemic inflammation? FIRAS AL-NIAIMI, MSC, MRCP, EBDV, is a world-renowned experienced professor in laser and clinical dermatology based in London and also affiliated to Aalborg University in Denmark. His private practice in London is split between Harley street and the Taktouk clinic in Knightsbridge. WASSIM TAKTOUK, MD, of The Taktouk clinic, Knightsbridge, London email have often been found in rosacea patients, in addition to kallikrein-5, matrix metalloproteinases 2 and 9 and increasedmast cell infiltration 1,2 . It is well-established that kallikrein-5 cleaves the anti-microbial peptide cathelicidin to its more active form of LL37, which is pro- inflammatory and angiogenic (forming new vessels). Interestingly, high expression of cathelicidin has also been found in the colonic mucosa of inflammatory bowel disease patients signalling just one example of the potential link between the skin and gut system, often referred to as the ‘gut-skin axis’ 3 . Expanding on the above, the ‘gut-brain-skin axis’ is a term that has been existent in medical literature for a period of time, linking certain inflammatory skin conditions with stress and gut-related pathology 4 . In recent years, a better understanding has shed more light on rosacea and its systemic links beyond the skin. Several large case-control observational studies have shown an association between rosacea and several systemic diseases and co- morbidities, including gastrointestinal, cardiovascular, | September/October 2021 39 | ROSACEA | AESTHETIC FEATURE