Interview with Dr Amode: "Better understanding of psoriasis."

"Plaque psoriasis, or psoriasis vulgaris, is the most common form, characterised by erythematous, scaly plaques of variable size that most frequently appear on the knees, elbows or lower back. This clinical presentation affects the majority of patients. We can also identify several common topographical variants, such as seborrhoeic region psoriasis, scalp psoriasis, nail psoriasis (which may occur in isolation), and inverse psoriasis affecting the flexural folds."

"Psoriasis is a multifactorial inflammatory disease, which includes genetic predisposition factors. It can therefore be transmitted vertically, but this is not an obligatory autosomal dominant transmission. It is a more complex form of inheritance, which does not systematically occur in offspring. However, psoriasis is not transmitted horizontally, that is to say from one individual to another. It is not a contagious disease, as an infectious disease might be."

"Psoriasis is a condition characterised by systemic inflammation. During severe flares of psoriasis, cholestatic hepatitis (liver involvement) has been described. The psoriatic arthritis reflects involvement of the joints and entheses. It should be noted that skin is to be understood in a broad sense, with possible involvement of skin appendages (nails) and mucous membranes (oral, anal, genital)."

"It is possible to suffer from both conditions simultaneously. Psoriasis can "eczematise" if the environment is favourable. We can thus have cases of psoriasis that resemble eczema, making them difficult to distinguish and causing diagnostic uncertainty between the two diseases. This is where a biopsy may be indicated. That said, this is not a particularly common association."

"It is not possible to prevent the onset of psoriasis. And preventing the disease’s onset in predisposed individuals? That is unknown; it can occur at any time. One cannot predict if, or when, the disease will be triggered in predisposed individuals. Acute stress is often a precipitating factor. In cases where the disease is established, it is possible to address the triggering factors: reduce the level of stress daily, limit the alcohol consumption, etc.

In cases where the disease is confirmed, it is possible to address the triggering factors: reduce daily stress levels, limit alcohol consumption. As a general recommendation, to control comorbidities (factors associated with the disease), a physical activity in an endurance-based mode and tailored to regular fitness levels, a diet balanced in the Mediterranean style, a smoking cessation.

"One of the main misconceptions is that psoriasis can be transmitted horizontally to those around us. However, this is not the case. Being in contact with someone who has psoriasis does not mean you can catch it. You can touch a psoriasis plaque without any risk. It's important to reassure people on this point."

Other misconceptions circulate about psoriasis, for example the idea that it primarily affects people with alcoholism. Certainly, alcohol is an aggravating factor for the disease, but psoriasis is not a direct consequence of alcoholism.

It is often said that psoriasis is a ‘serious disease’. This is not entirely accurate. Cutaneous psoriasis, when limited in extent and without psychological or social impact, is not considered serious per se. However, it can have significant consequences: social isolation, depression, or even metabolic complications, the precise links of which remain to be clarified. Furthermore, severe forms of psoriasis are associated with a documented increased cardiovascular risk.

"Psoriasis is epidemiologically associated with cardiovascular comorbidities. There are higher rates of myocardial infarction, strokes, excess weight and diabetes in patients with psoriasis. There is a statistical association, but this does not equate to a causal relationship. In severe psoriasis, one might consider the well-documented role of systemic inflammation. The other complications are psychosocial. Having visible lesions can affect self-esteem, mood, social life and sexual well-being."

"Psoriasis does not leave scars since the lesions are purely epidermal. There is no involvement of the basement membrane, and therefore no permanent scarring. However, post-inflammatory hypopigmentation (lighter patches than the patient’s normal skin) or hyperpigmentation (darker patches) may develop following psoriatic lesions. These changes in skin colouring are transient and eventually fade. The resolution of these spots is often observed over several weeks"

These pigmentation changes are a consequence of damage caused to melanocytes by inflammation : either hypopigmentation if their activity is reduced or if they are destroyed, or hyperpigmentation if they have increased their activity in response to inflammation.