Can psoriasis be completely cured?

Recently, I saw someone asking about the treatment of psoriasis. Today, I will give a relatively detailed popular science introduction to psoriasis. It is a long article, but it is very informative. You can jump directly to the part you are interested in. But if you have patience, I still hope that everyone can systematically understand this troublesome disease.

01. About Psoriasis

First, let us give a comprehensive introduction, hoping it will help everyone to correctly understand and treat psoriasis.

Many people get nervous and anxious when they have psoriasis, especially when the doctor tells you that it is a "lifelong disease" (in plain words, it will accompany you for life and cannot be cured for the time being). So at the beginning, I must emphasize a few very basic but important things:

Don't be scared by "incurable". At present, most diseases may not be "curable", such as allergic diseases, high blood pressure, diabetes, etc., and even colds often "come back". So don't get hung up on "incurable". On the contrary, if anyone tells you that psoriasis can be "cured", there is a 100% problem, don't believe it. They may mix a lot of hormones or heavy metals in the "medicine", which will only make the condition worse and hurt the body;

Although it cannot be cured, there are many drugs for psoriasis now, and various targeted drugs have been developed (detailed popular science is available below, it is worth reading patiently) that can be used, either orally or by injection, and can cure very well. But the prerequisite is to go to a regular hospital for medical treatment and medication;

Psoriasis is not an infectious disease and is not contagious from person to person;

Emotions and stress can trigger the onset and aggravation of psoriasis, but can also alleviate the condition. Therefore, it is important to adjust your mentality.

The above points are summarized in the hope of helping everyone quickly let go of their psychological burdens and look at this disease rationally and scientifically.

02. What is psoriasis?

Psoriasis is an immune-mediated chronic, recurrent, inflammatory, systemic disease induced by the interaction between individuals and the environment (emphasis: it is not a simple skin disease, but an immune-related disease). The typical clinical manifestations are localized or widespread scaly erythema or plaques. Psoriasis can appear anywhere on the body, most commonly on the scalp, limbs and other parts. It is mainly divided into four types: psoriasis vulgaris, pustular psoriasis, erythrodermic psoriasis and articular psoriasis. Among them, plaque psoriasis vulgaris is the most common clinically, accounting for about 80%-90% of the total cases1.

Psoriasis is a common disease in dermatology, with a global prevalence of between 0.09% and 11.43%2, and a prevalence of about 0.47% in China3. Psoriasis can occur at any age, but most cases occur before the age of 40, and there is no obvious gender difference.

03. Why do people get psoriasis?

The cause of psoriasis involves many factors and is very complex. The exact cause has not yet been fully elucidated. However, the common triggering factors that have been found are:

Environmental factors: The most typical ones are emotions and stress. Studies have shown that stress, mental stress, sleep disorders, overwork, etc. may cause psoriasis to occur, worsen, or relapse; and when mental stress is relieved, the condition will also be alleviated. This is why we emphasized at the beginning that we must adjust our mentality and not be too nervous. In addition, common environmental triggers include: smoking, alcoholism, local damage (such as trauma) or infection.

Genetic factors: Studies show that about 50% to 30% of psoriasis patients have a family history. But it does not mean that if you have psoriasis, you will definitely pass it on to your children. When one parent has psoriasis, the incidence rate of their children is about 20%; and when both parents have the disease, the incidence rate of their children will increase to 65%. So if your spouse does not have psoriasis, you don't have to worry too much about passing it on to your children.

Immune factors: The reason why psoriasis is not a simple skin problem, but an immune-related inflammatory disease , is because studies have found that the occurrence of psoriasis may be related to the overactivity of part of the patient's immune system6. The skin is one of the important immune organs of the human body. Under normal circumstances, after the human body is stimulated, various immune cells in the body begin to respond quickly, ordering skin cells to "work overtime" and accelerate keratinization and proliferation to enhance the skin's resistance. However, if the immune system is unbalanced and overactive for various reasons, this "response" will become disordered and excessive, constantly transmitting wrong instructions, causing keratin to accumulate continuously, leading to psoriasis. Understanding the pathogenesis of psoriasis from an immune perspective is a major step forward. It is precisely because of "seeing the essence through the phenomenon" that the precise treatment of psoriasis has become possible.

Psoriasis causative factors

04. How to treat psoriasis?

The treatment of psoriasis is closely related to the severity of the disease. Patients can use a simple "slap count" to roughly assess the severity of their disease, that is, to estimate the "body surface area" (BSA):

The skin lesions on the whole body are less than 3 palms, that is, BSA <3%, which is mild;

The skin lesions on the whole body are greater than or equal to 3 palms and less than 10 palms, that is, BSA 3%~<10%, moderate

The total body skin lesion area is greater than or equal to 10 palms, that is, BSA 3% ≥ 10%. In severe clinical cases, in addition to BSA, doctors will also combine the "Psoriasis Area and Severity Index" (PASI) and "Dermatology Life Quality Index" (DLQI) and other dimensions to conduct a more comprehensive assessment of patients.

After evaluating the condition, the next step is "treatment as needed". The treatment idea can be summarized in one sentence: as the condition progresses, the treatment is also "from the outside to the inside", step by step. From relieving surface symptoms to going deep into the pathogenic pathway to "targeted" solution to the problem.

1. Mild: topical medication treatment (also known as "local treatment")

Topical medications are the first choice for the treatment of psoriasis. Common medications include:

Body lotion (don’t underestimate moisturizing, it’s the foundation)

Glucocorticoids (super-potent, strong, medium-potent, weak)

Vitamin D3 derivatives (such as calcipotriol and tacalcitol)

Retinoic acid drugs

Calcineurin inhibitors, etc.

Among them, glucocorticoids are the most commonly used in clinical practice. Because they have anti-inflammatory and immunosuppressive effects, they are very suitable for dealing with inflammatory diseases such as psoriasis, so they take effect quickly and have obvious therapeutic effects. However, hormone drugs cannot be used or stopped suddenly, which can easily lead to rebound or even aggravation, and they cannot be used on a large area of ​​the body. And the strength of the hormone selected is different for different conditions. Therefore, you must strictly follow the doctor's instructions and never abuse them yourself.

2. Moderate to severe cases - physical therapy/systemic treatment

When the condition reaches moderate or severe stage, topical medication alone is not enough and new treatment plans are needed. There are two main types of treatment: physical therapy and systemic therapy .

Physical therapy : including ultraviolet therapy (phototherapy) and bath therapy. Ultraviolet therapy: through a certain wavelength of ultraviolet light irradiation skin surface and converted into heat energy, chemical energy and bioenergy to play a certain anti-inflammatory and immunomodulatory role. It is currently believed that narrow spectrum ultraviolet light (NB-UVB) with a wavelength of 311-313 nm has a good effect on psoriasis, and psoralen long-wave ultraviolet photochemotherapy (PUVA) can also effectively remove skin damage and relieve psoriasis symptoms. If the NB-UVB irradiation alone is not effective, local or systemic medication will be combined clinically. Bath therapy: hot springs, sea water, and sand are used for bathing. The principle is mainly to exert therapeutic effects through the warm effect, pressure mechanical effect, or various physical and chemical factors such as trace elements brought by these external substances. There is also a kind of sunbathing, which is consistent with the principle of "ultraviolet therapy". However, the ultraviolet rays in sunlight are not filtered and have a certain lethality to the skin, so it must not be exposed to the sun, and protection work must be done well.

Systemic therapy : Systemic therapy can be said to be a "high-level" method for treating psoriasis in clinical practice. In recent years, many innovative therapies have also appeared in this field. We can simply divide systemic therapy into two categories based on whether there is a therapeutic target: non-targeted therapy and targeted therapy.

3. Moderate to severe systemic treatment (non-targeted treatment)

As mentioned above, the occurrence of psoriasis is related to an overactive immune system, so immunosuppression is a treatment idea. Commonly used clinical drugs such as methotrexate, cyclosporine, and acitretin are all traditional oral immunosuppressants. Taking methotrexate as an example, it can reduce the proliferation rate of keratinocytes by inhibiting cell growth and reproduction. It has shown good efficacy for all types of psoriasis and is currently one of the most commonly used traditional drugs for the treatment of psoriasis7.

However, the biggest drawback of this type of drug is the lack of a clear "therapeutic target", which means that they are a comprehensive suppression of the human immune system, similar to "carpet bombing". As a result, some parts that do not need to be suppressed are also affected, causing side effects. For example, the two most important adverse reactions of methotrexate are bone marrow suppression and hepatotoxicity, while acitretin may cause adverse reactions such as abnormal blood lipid metabolism. Because of this, some doctors say that using this type of drug is like "walking a tightrope": you have to treat the disease while balancing safety. Moreover, patients cannot use it for a long time, and regular follow-up and examinations should be carried out during use.

4. Moderate to severe systemic treatment (targeted therapy)

As research on psoriasis continues to deepen, we have clarified some core pathogenic pathways and pathogenic factors, making targeted treatment possible.

Targeted therapy, as the name implies, is to precisely intervene in one or several specific pathogenic factors ("targets"). The advantage is that it is more accurate, efficient and safer than traditional immunosuppressants. So what targets have been found for treatment? We can briefly introduce them according to the following figure.

Target 1: Tumor necrosis factor α (TNF-α). Tumor necrosis factor α is the focus target of the first generation of biologics for psoriasis. It is a proinflammatory cytokine that is in the upstream initiation stage of the inflammatory cascade and can induce the production of downstream keratinocytes.

Treatment idea: Inhibit excessive TNF-α production, thereby blocking excessive production of keratinocytes and controlling psoriasis.

Treatment method: Large molecule drugs (biological agents), so they need to be injected or infused.

Target 2: Interleukin cytokines (IL). Interleukin (IL), also known as interleukin, is an immunomodulatory protein. IL-23 and IL-17 can induce the production of downstream keratinocytes. They are key driving cytokines for the onset of psoriasis and are also the focus targets of second-generation biological agents.

Treatment idea: Inhibit excessive IL-23/17 production, thereby blocking excessive production of keratinocytes and controlling psoriasis.

Treatment method: Large molecule drugs (biological agents), so they need to be administered by subcutaneous injection.

Target 3: Tyrosine kinase 2 (TYK2). This is a hot target in the field of immunology in recent years. TYK2 is a kinase in cells that is responsible for mediating the signal transduction of IL-23, IL-12 and type I IFN cytokines. Simply put, TYK2 is like a signal switch: when the switch is turned on, the signal is unblocked, and IL-12 and IL-23 can form TNF-α and IL-17 downstream; when the switch is closed, the signal is blocked, and these inflammatory factors downstream cannot be generated. So to some extent, it and the above two targets have the same therapeutic ideas.

Treatment idea: Inhibit TYK2, thereby blocking the TYK2-mediated IL-23, IL-12 and type I IFN signaling pathways.

Treatment: Small molecule drugs, administered orally.

Target 4: Phosphodiesterase 4 (PDE-4). PDE-4 is a metabolic enzyme that mainly exists in immune cells and can break down intracellular cyclic adenosine monophosphate (cAMP) into adenosine monophosphate (AMP) that can promote inflammation. Therefore, inhibiting PDE-4 activity can increase cAMP concentration, thereby reducing the formation of pro-inflammatory factors, promoting the production of anti-inflammatory mediators, and adjusting the inflammatory response of psoriasis.

Treatment ideas: Inhibit PDE-4 activity and reduce cAMP decomposition.

Treatment: Small molecule drugs, administered orally.

Targeted drugs are a major advancement in the treatment of psoriasis, which have raised the effectiveness, safety and convenience of treatment to a higher level, and even made "clinical cure" (that is, the disease is well controlled and does not affect normal life at all) an achievable goal. This is really a world of difference from the treatment environment in the past! Moreover, there are both convenient oral medications and injections. Patients can choose the treatment method that suits them according to their own conditions to meet the needs of precision and individualization. In addition, new drugs are also gradually entering the medical insurance, and the economic burden is getting lighter and lighter. So I think that in this era, psoriasis patients must have confidence, maintain a positive attitude, and go to regular hospitals to seek help from professional doctors. I believe that everyone can return to a wonderful life.

1. "Guidelines for the diagnosis and treatment of psoriasis in China (2023 full version)", Chinese Journal of Dermatology, Vol. 56, No. 7, July 2023

2. World health organization. Global Report on Psoriasis［Ｒ］． Geneva: WHO, 2016: 7-9.

3. Ding Xiaolan, Wang Tinglin, Shen Yiwei, et al. Epidemiological survey of psoriasis in six provinces and cities in China [J]. Chinese Journal of Dermatology and Venereology, 2010, 24 (7): 598-601.

4. Winchell SA, Watts RA. Relaxation therapies in the treatment of psoriasis and possible pathophysiologic mechanisms［J］. J Am Acad Dermatol, 1988,18(1 Pt 1):101⁃104. doi: 10.1016/s0190⁃ 9622(88)70015⁃8.

5. Zhang

6. Lowes, Michelle A., Anne M. Bowcock, and James G. Krueger. "Pathogenesis and therapy of psoriasis." Nature 445.7130 (2007): 866-873.

7. Gambichler, Thilo, et al. "Narrowband UVB phototherapy in skin conditions beyond psoriasis." Journal of the American Academy of Dermatology 52.4 (2005): 660-670.