Psoriasis is a chronic autoimmune skin condition that causes rapid skin cell buildup. In a person without psoriasis, skin cells are born in the deeper layers of the skin and slowly rise to the surface over the course of about a month, where they eventually die and flake off. In psoriasis, the immune system sends out faulty signals that put this process into hyperdrive. The skin cells begin to multiply far too quickly, rising to the surface in just a few days instead of a few weeks.

The body cannot shed these excess skin cells fast enough, so they pile up on the surface of the skin. This rapid accumulation of cells is what creates the characteristic thick, red, inflamed patches covered with silvery-white scales, known as plaques.

To understand this process, it helps to use an analogy. Think of your skin production as a factory assembly line that normally produces new cells at a steady, manageable pace, with older cells being neatly discarded at the end of the line. In psoriasis, an overactive immune system acts like a foreman who has panicked, screaming at the assembly line to run at ten times its normal speed. The factory churns out cells so quickly that they pile up on the loading dock before they can be properly processed and shipped out. This chaotic pile-up of immature, built-up skin cells is what forms the psoriatic plaques.

In my experience, patients often live with psoriasis for years thinking it’s “just dry skin” until a flare becomes too painful or visible to ignore.

The exact cause of psoriasis is not fully understood, but it is known to be a complex interplay between genetics and the immune system.

A Dysfunctional Immune System: Psoriasis is, at its core, an autoimmune disease. In a healthy person, the immune system’s T-cells are responsible for identifying and attacking foreign invaders like bacteria and viruses. In psoriasis, these T-cells mistakenly attack healthy skin cells. This misguided attack triggers a cascade of inflammatory responses. The overactive T-cells produce large amounts of inflammatory chemicals called cytokines, particularly tumor necrosis factor-alpha (TNF-alpha), Interleukin-17 (IL-17), and Interleukin-23 (IL-23). These cytokines are the key signals that tell the skin cells to go into overdrive and reproduce at an accelerated rate, leading to the formation of psoriatic plaques (National Psoriasis Foundation, n.d.). This understanding of the specific inflammatory pathways is what has led to the development of modern, targeted biologic therapies.

Genetic Predisposition: Psoriasis has a strong genetic component and frequently runs in families. Having a parent with psoriasis significantly increases your risk of developing the condition. However, not everyone who inherits the genes for psoriasis will get it. Scientists have identified numerous genes associated with psoriasis, many of which are related to immune system function. It is believed that individuals must have a specific combination of these predisposing genes and then be exposed to an environmental “trigger” to activate the disease.

Patients often ask if it’s caused by poor hygiene, absolutely not. Psoriasis is an internal immune imbalance, not a skin infection.

You can develop psoriasis if you have a genetic predisposition and are exposed to triggers that activate the immune system. A trigger is something in the environment or within the body that can cause the first onset of psoriasis or cause a flare-up in someone who already has the condition.

Common triggers for psoriasis include:

• Infections: Certain infections can kickstart the immune system and trigger a psoriatic flare. Strep throat is a well-known trigger, particularly for a specific type of psoriasis called guttate psoriasis.
• Skin Injury (The Koebner Phenomenon): For many people with psoriasis, an injury to the skin can trigger a new psoriatic plaque to form at that exact spot. This can include a cut, scrape, bug bite, severe sunburn, or even a tattoo or vaccination site.
• Stress: High levels of psychological stress are a major trigger for psoriasis flare-ups. The stress hormones in the body can have a profound effect on the immune system.
• Certain Medications: Some medications are known to trigger or worsen psoriasis. These include lithium (used to treat bipolar disorder), beta-blockers (for high blood pressure), antimalarial drugs, and the rapid withdrawal of oral or systemic corticosteroids.
• Smoking and Heavy Alcohol Consumption: Both smoking and excessive alcohol use are known to worsen psoriasis and can make treatments less effective.
• Weather: Cold, dry weather can make psoriasis worse, while some people find their symptoms improve with exposure to sunlight and humidity.

Clinically, I find that a clear trigger like an infection or stressful event is often the spark for a patient’s first major flare, even if they’ve had mild symptoms for years.

Psoriasis can present in several different forms, and a person may have more than one type over their lifetime.

• Plaque Psoriasis: This is the most common form, affecting about 80-90% of people with the condition. It is characterized by the classic well-defined, raised, red plaques with silvery-white scales. They can appear anywhere but are most common on the elbows, knees, scalp, and lower back.
• Guttate Psoriasis: This type often appears suddenly in childhood or young adulthood, frequently after a streptococcal infection. It is characterized by small, drop-like, red, scaly spots that appear over large areas of the body, such as the trunk, arms, and legs.
• Inverse Psoriasis: This type appears in skin folds of the body, such as the armpits, groin, under the breasts, and in the buttocks. It appears as smooth, bright red, inflamed patches without the thick scaling seen in plaque psoriasis, often worsened by sweat and friction.
• Pustular Psoriasis: This is a less common form characterized by widespread white pustules (blisters of non-infectious pus) surrounded by red skin.
• Erythrodermic Psoriasis: This is a rare and very severe inflammatory form of psoriasis that affects nearly the entire body surface at once. The skin appears bright red and peels off in sheets. It can be life-threatening and requires immediate medical attention.

Psoriasis can look and feel different from person to person. The severity, type, and location determine how it presents.

Skin Symptoms: The appearance varies by type, but common skin symptoms include:

• Red patches of skin covered with thick, silvery-white scales.
• Dry, cracked skin that may bleed.
• Itching (pruritus), burning, or soreness.

Nail Psoriasis: About half of all people with psoriasis will experience changes in their fingernails and toenails. These can include:

• Tiny pits or dents in the nail surface.
• Yellow-brown discoloration.
• Crumbling of the nail.
• Separation of the nail from the nail bed (onycholysis).

Psoriatic Arthritis (PsA): This is a major and serious comorbidity. Up to 30% of people with psoriasis will also develop psoriatic arthritis, a form of inflammatory arthritis that causes pain, stiffness, and swelling in and around the joints. PsA can affect any joint in the body and, if left untreated, can lead to permanent joint damage.

In the clinic, I’ve seen patients distressed not just by the physical discomfort, but by the emotional burden, especially when visible areas like the hands or face are affected.

Psoriasis is often diagnosed through clinical examination, based on the appearance and distribution of skin lesions.

• The characteristic appearance and distribution of the plaques are usually sufficient for a confident diagnosis.
• In some cases, if the diagnosis is uncertain, the doctor may perform a skin biopsy. A small piece of the affected skin is removed and examined under a microscope by a pathologist, which can confirm the changes characteristic of psoriasis.

In my practice, I also screen for associated risks like high blood pressure, diabetes, and obesity, as psoriasis is linked with metabolic syndrome.

There is no cure for psoriasis, but many treatments can reduce symptoms, control flare-ups, and improve quality of life. The treatment plan is tailored to the individual and depends on the type, location, and severity of the psoriasis. Doctors often use a “treatment ladder” approach, starting with the mildest therapies.

1. Topical Treatments (for Mild to Moderate Psoriasis): These are medications applied directly to the skin.

• Corticosteroids: These anti-inflammatory creams and ointments are a mainstay of treatment.
• Vitamin D Analogues: Synthetic forms of vitamin D (like calcipotriene) work by slowing down skin cell growth.
• Topical Retinoids: Derivatives of vitamin A that can help normalize skin cell activity.
• Calcineurin Inhibitors: Often used for sensitive areas like the face or skin folds.
• Salicylic Acid and Coal Tar: Older but still effective treatments found in shampoos and creams to help remove scale.

2. Phototherapy (for Moderate to Severe Psoriasis): This involves exposing the skin to controlled amounts of natural or artificial ultraviolet (UV) light.

• UVB Phototherapy: The skin is exposed to ultraviolet B light from a special lamp. This must be done regularly in a doctor’s office.
• PUVA: This combines a light-sensitizing medication (psoralen) with exposure to ultraviolet A light.

3. Systemic Medications (for Moderate to Severe Psoriasis and PsA): These are drugs that work throughout the body, taken orally or by injection.

• Methotrexate: A powerful drug that suppresses the immune system and slows down skin cell growth.
• Cyclosporine: A potent immunosuppressant used for short-term control of severe flares.
• Acitretin: An oral retinoid that can control skin cell growth.

4. Biologic Therapies: This is the newest and most targeted class of drugs for moderate to severe psoriasis and psoriatic arthritis.

• These are protein-based drugs, given by injection or infusion, that block a specific part of the overactive immune response.
• They target specific cytokines, such as TNF-alpha, IL-17, or IL-23, which are the key drivers of the inflammation in psoriasis.
• Biologic therapies have revolutionized the care of severe psoriasis, offering many patients the chance to achieve and maintain clear or almost clear skin. However, they are highly specialized medications that can have significant costs, with availability varying depending on the region and healthcare system.

Patients who respond to biologics often tell me it’s life-changing, they go from avoiding social contact to living comfortably again. The key is finding the right treatment fit.

Psoriasis is much more than a cosmetic nuisance; it is a chronic, systemic autoimmune disease that can have a significant impact on a person’s physical and emotional well-being. It is essential to remember that it is not contagious and not the result of poor hygiene. The disease is driven by a combination of genetics and an overactive immune system, which causes skin cells to grow too quickly. While there is no cure, a vast arsenal of effective treatments, from topicals to biologics, can help most people manage their symptoms, control the disease, and live a high-quality life. I often reassure patients: psoriasis isn’t just skin deep, but it’s also not something you have to face alone. The right treatment plan can restore both skin and confidence.

American Academy of Dermatology (AAD). (n.d.). Psoriasis: Overview. Retrieved from https://www.aad.org/public/diseases/psoriasis/what-is-psoriasis

National Psoriasis Foundation. (n.d.). About Psoriasis. Retrieved from https://www.psoriasis.org/about-psoriasis/

Mayo Clinic. (2024). Psoriasis. Retrieved from https://www.mayoclinic.org/diseases-conditions/psoriasis/symptoms-causes/syc-20355840