Interview with Dr. AMODE: "Better Understanding Psoriasis."

"Plaque psoriasis, or vulgar psoriasis, is the most common form, characterized by erythematous, scaly plaques of variable size that most often appear on the knees, elbows, or lower back. This clinical presentation affects the majority of patients. We can also mention certain common topographic variants, such as seborrheic-region psoriasis, scalp psoriasis, isolated nail psoriasis, and inverse psoriasis affecting the flexural folds."

"Psoriasis is a multifactorial inflammatory disease that includes genetic predisposition factors. It can thus be transmitted vertically, but this is not a strictly autosomal dominant mode of inheritance. The pattern is more complex and does not invariably affect offspring. In contrast, psoriasis is not spread horizontally, meaning from one individual to another. It is not a contagious disease, as an infectious disease might be."

"Psoriasis is a disorder characterized by systemic inflammation. During severe psoriasis flares, cholestatic hepatitis (liver involvement) has been reported. The psoriatic arthritis reflects involvement of the joints and entheses. It should be noted that the 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 "eczematize" if the underlying conditions are favorable. We may thus encounter cases of psoriasis that resembleeczema, making them hard to distinguish and leading to diagnostic uncertainty between the two diseases. This is where a biopsy may be indicated. That said, this association is not particularly common."

"It is not possible to prevent the onset of psoriasis. And preventing the disease from being triggered when one is predisposed? We don’t know; it can happen at any time. We cannot predict if or when the disease will flare in predisposed individuals. Acute stress is often a precipitating factor. In cases where the disease is confirmed, it is possible to address the triggering factors: reduce the level of stress daily, limit the alcohol consumption, etc.

In confirmed cases of the disease, it is possible to address triggering factors: reducing daily stress levels and limiting alcohol consumption. Generally, to manage comorbidities (factors associated with the disease), one can recommend a physical activity regimen that is endurance-based and tailored to regular fitness levels, a diet balanced in a Mediterranean style, a smoking cessation."

"One of the main misconceptions is that psoriasis can be transmitted horizontally to people around the patient. However, this is not the case. When you come into contact with someone who has psoriasis, you cannot contract it. You can safely touch a psoriasis plaque without any risk. People need to be reassured on this point."

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

It is also often said that psoriasis is a “serious disease.” This is not entirely accurate. Cutaneous psoriasis, when it is limited in extent and without psychological or social impact, is not considered serious in itself. However, it can have significant consequences: social isolation, depression, or metabolic complications, the exact links of which remain to be clarified. Moreover, 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, stroke, overweight, and diabetes among patients with psoriasis. Although this statistical association is well documented, it does not imply a causal relationship. In severe psoriasis, the role of systemic inflammation, which is well documented, can be considered. Other complications are psychosocial. Having visible lesions can affect self-esteem, mood, social life, and sexual life."

"Psoriasis does not leave scars, as it involves only epidermal lesions. There is no involvement of the basement membrane, so no permanent scarring occurs. However, post-inflammatory hypopigmentation (lighter patches compared with the patient’s skin) or hyperpigmentation (darker patches) may develop following psoriatic lesions. These changes in skin pigmentation are transient and eventually fade. The resolution of these spots is often observed over several weeks."

These pigmentation changes are a consequence of inflammation-induced damage to melanocytes : either hypopigmentation when their activity is diminished or they are destroyed, or hyperpigmentation when their function increases in response to inflammation.