Erythroderma (exfoliative dermatitis), first described by Von Hebra in 1868, manifests as a cutaneous inflammatory state, with associated skin barrier and metabolic dysfunctions. The annual incidence of erythroderma is estimated to be 1-2 per 100 000 population in Europe with a male preponderance. Erythroderma may present at birth, or may develop acutely or insidiously (due to progression of an underlying primary pathology, including malignancy). Although there is a broad range of diseases that associate with erythroderma, the vast majority of cases result from pre-existing and chronic dermatoses. In the first part of this two-part concise review, we explore the underlying causes, clinical presentation, pathogenesis and investigation of erythroderma, and suggest potential treatment targets for erythroderma with unknown causes.

Erythroderma (exfoliative dermatitis) is associated with important metabolic changes that include an enhancement in energy expenditure. The key components to total energy expenditure (TEE) include basal metabolic rate (~68% of TEE), physical activity (~22% of TEE) and thermic effect of food (~10% of TEE). In the erythrodermic state, there are likely multiple contributors to the increase in basal metabolic rate, such as 'caloric drain' resulting from increased evaporation of water from enhanced transepidermal water loss, increased activity of the cardiovascular system (including high-output cardiac failure), increased nonshivering thermogenesis and hormonal changes such as hypercortisolaemia. A change in the patient's level of physical activity and appetite as a result of ill health status may further impact on their TEE and energy consumption. In Part 2 of this two-part concise review, we explore the key constituents of energy homeostasis and the potential mechanisms influencing energy homeostasis in erythroderma, and suggest much-needed dietetic management strategies for this important condition.

blockade in an NS mouse model, showed no reduction in cutaneous inflammation, which would further argue against a significant Th2 skew in NS and a treatment benefit of dupilumab. 5 However, the unopposed serine protease activity and reduced inhibition of kallikreins together with eosinophilic activation, increased numbers of mast cells and elevated levels of TSLP in NS stimulate differentiation of Th0 to Th2 cells. 6,7 This initiates the development of lesions similar to those observed in AD. Interestingly, the reduced levels of Th2 cytokines in some patients with NS could be explained by downregulation via Th17 pathways. 4 IL-17, IL-19 and Th17/IL-23 pathways were upregulated in skin and blood of 15 patients with NS aged 6-43 years, and IL-17 levels were higher than in patients with AD. [2][3][4] It is possible that the inflammation is different in patients with NS than patients with AD; they may have a different skew of Th2 and Th17 pathways and this relative skew might change with age.The exact immune activation in NS is currently unclear. Which biologic treatment, if any, that is best suited to individual patients with NS remains to be defined. One study including three patients with NS observed increased Th1 marker levels in patients with NS similar to that of patients with AD and patients with psoriasis. 2 A recent case report demonstrated a clinical effect of treatment with ustekinumab, which is an IL-12/-23 antibody, in a 15-year-old girl with NS. 8 Importantly, antiinflammatory treatment cannot treat the primary skin barrier defect, and patients with NS need to continue applying emollients daily.We conclude that treatment with dupilumab in our adult patient with NS led to the dramatic reduction in EASI. Further studies are needed to evaluate the immune profile of patients with NS.

The role of diet and nutrition in the management of chronic inflammatory skin conditions such as eczema, psoriasis and acne is one of the commonest questions asked by patients. Despite this, there is little guidance or training to help healthcare professionals provide disease-specific evidence-based recommendations to patients. Furthermore, growing evidence supports the role of diet and nutrition in the management of skin conditions such as psoriasis and atopic eczema. We sought to explore dermatology professionals’ experiences of patients’ dietary habits in an outpatient setting. We circulated a questionnaire to members of the British Dermatological Nursing Group and the British Association of Dermatologists. We collected demographic data, along with information on how frequently professionals were asked about diet by patients, how confident they felt responding to questions and concerns expressed regarding dietary restrictions, and whether dietitian input or nutrition training would be of benefit to their practice. Three of the authors received funding from the Psoriasis Association. We received 95 responses from dermatology nurses and 64 from doctors. Over 60% of respondents held senior positions with over 10 years of experience. Almost 100% of respondents reported being asked about diet by patients and 73.1% did not feel confident when answering these questions. Patients were most commonly asked about nutrition in relation to inflammatory conditions such as eczema (95.3%), acne (95.3%) and psoriasis (76.6%). All doctors and 97.8% of nurses reported having experienced patients restricting their diet without supervision, and the majority expressed concerns about such dietary modifications. Dairy, gluten and refined sugar were the most commonly excluded foods. Professionals also reported that patients admitted to following restrictive diets and undertaking ‘food intolerance testing’ that they had encountered online. Over 90% of respondents felt that additional nutrition training and access to specialist dietician support would be of benefit to dermatology practice. Dermatology professionals are frequently asked about nutrition and the role of diet yet often lack confidence in responding to these enquiries. Dermatology patients appear vulnerable to dietary misinformation presented online regarding ‘intolerance tests’, and this has the potential to worsen with ongoing delayed access to secondary care. There are also concerns regarding unsupervised restrictive diets, which can negatively impact patients’ mental health and predispose to eating disorders and nutritional deficiencies. Specialist nutrition training for dermatology professionals and the support of dietitians in the clinical setting would help address this unmet need and provide holistic patient care.