Psoriasis is a chronic autoimmune skin condition that, according to the World Health Organization, affects around 125 million people worldwide—approximately 2–3% of the global population. Prevalence varies by region and ethnic background, ranging from about 0.1% to 11%. The condition is more common in Northern Europe than in Asia.
In Lithuania, the Universal Lithuanian Encyclopedia estimates that around 120,000 people are affected by psoriasis, accounting for nearly 4% of the population—slightly above the global average.
The actual number of cases may be higher, as some individuals do not seek medical attention or choose to self-treat. Although psoriasis cannot be cured, it can be effectively managed with modern treatments and appropriate lifestyle choices under the supervision of a dermatologist.
What is psoriasis?
Psoriasis is a chronic, autoimmune, and completely non-contagious skin condition caused by dysfunction of the immune system. Due to accelerated skin cell turnover, red plaques covered with silvery scales form on the skin’s surface. The condition can affect different parts of the body and vary in severity, but it most commonly appears on the elbows, knees, scalp, and lower back.
Main types of psoriasis
Psoriasis is classified according to its location, appearance, and severity. Each type has specific characteristics and may require an individualised treatment approach.
Plaque psoriasis
Plaque psoriasis is the most common form of the condition. According to the StatPearls medical database, it accounts for approximately 80–90% of all psoriasis cases. It is characterised by clearly defined red plaques and papules covered with thick, silvery scales. This form is associated with the Auspitz sign—pinpoint bleeding when the scales are removed.
Lesions most often appear on the elbows, knees, lower back, and scalp. Plaques may itch, cause discomfort, and sometimes be painful.
Scalp psoriasis
Scalp psoriasis is one of the most common localisations of the condition. Typical symptoms include red plaques covered with thick, whitish scales, intense itching, a burning sensation, and dryness. Lesions may extend beyond the hairline to the forehead, neck, or behind the ears. It is often confused with dandruff, but psoriasis is characterised by thicker scales and more pronounced red lesions.
Nail psoriasis
Nail psoriasis affects the fingernails and toenails. It may be recognised by small pits on the nail surface, colour changes such as yellowish or brown spots, separation of the nail from the nail bed, and thickened or cracked nails. In addition to aesthetic concerns, nail psoriasis may interfere with daily activities and is often associated with psoriatic arthritis.
Psoriatic arthritis
Psoriatic arthritis is a chronic inflammatory joint condition associated with psoriasis, affecting approximately 20–30% of people with skin psoriasis. It is an immune-mediated condition that affects joints, tendons, and ligaments, causing pain, swelling, stiffness, and reduced mobility.
It most commonly affects the small joints of the hands and feet, although the spine and sacroiliac joints may also be involved. Typical symptoms include morning stiffness lasting longer than 30 minutes, sausage-shaped swelling of fingers or toes (dactylitis), and tenderness at tendon attachment points (enthesitis).
If left untreated, psoriatic arthritis may lead to irreversible joint damage, so early diagnosis and appropriate treatment are essential.
Pustular psoriasis
Pustular psoriasis is a more severe form of the condition in which white, pus-filled blisters (pustules) develop on reddened skin. These pustules are sterile and non-contagious. This form may be localised, most commonly on the palms and soles, or spread across the body. It may be accompanied by fever and weakness, and in some cases requires urgent medical attention.
Genital psoriasis
Genital psoriasis appears in sensitive areas such as the groin, genital region, and perineum. In these areas, plaques are usually smooth, bright red, and have little or no scaling due to the moist environment. Symptoms often include itching, burning, and discomfort.
Erythrodermic psoriasis
Erythrodermic psoriasis is a rare but the most severe form of the condition, affecting more than 90% of the body surface. The skin becomes bright red, intensely itchy, and peels over large areas. This form can be very painful and is often accompanied by systemic symptoms such as fever, dehydration, and chills. It may be life-threatening and usually requires hospital treatment. It often develops after the sudden withdrawal of systemic corticosteroids.
What triggers psoriasis?
Although the exact cause of psoriasis is not fully understood, several factors may contribute to its onset or flare-ups:
- Stress and emotional tension;
- Infections, especially streptococcal throat infections;
- Certain medications, including beta blockers, lithium, some antimalarial drugs, and NSAIDs;
- Skin injuries such as cuts, scratches, sunburn, or vaccination sites (Köbner phenomenon);
- Cold and dry weather;
- Alcohol consumption and smoking;
- Hormonal changes, including pregnancy, puberty, and menopause.
How is psoriasis treated?
Topical treatments
For milder forms, creams, ointments, or lotions are typically prescribed. These may include corticosteroids, vitamin D analogues, retinoids, salicylic acid, calcineurin inhibitors, and moisturisers. They help reduce inflammation and soften scales.
Light therapy
Light therapy involves controlled exposure of the skin to ultraviolet light. The most common methods are narrowband UVB therapy and the PUVA method, which combines UVA light with photosensitising agents. This treatment is often used for moderate psoriasis or when topical treatments are insufficient.
Systemic medications
Moderate to severe psoriasis may require oral or injectable medications that affect the entire body. These include methotrexate, cyclosporine, and acitretin. They suppress excessive immune responses and slow the growth of skin cells.
Biologic therapies
In severe cases, biologic medications targeting specific parts of the immune system may be prescribed. These are usually administered by injection and are considered when other treatments do not provide sufficient results.
Psoriasis and diet: What to avoid
There is no single diet proven to cure psoriasis, but certain foods may influence inflammation in the body.
It may be beneficial to include:
- Omega-3 sources such as fatty fish, flaxseeds, and walnuts;
- Antioxidant-rich foods like berries and leafy greens;
- Whole grains such as oats and brown rice;
- Probiotic foods including yoghurt, kefir, and fermented vegetables;
- Anti-inflammatory spices such as turmeric and ginger.
Foods that may be worth limiting include:
- Red and processed meat;
- Refined carbohydrates and sugar;
- Alcohol;
- Nightshade vegetables, which may trigger symptoms in some individuals;
- Dairy and gluten, if they worsen symptoms.
These recommendations are based on anti-inflammatory dietary principles similar to the Mediterranean diet, although strong evidence for one specific psoriasis diet is limited.
Frequently Asked Questions
What is scalp psoriasis?
Scalp psoriasis is a form of psoriasis affecting the scalp. It is characterised by red plaques covered with thick, silvery scales, along with itching and dryness. Unlike dandruff, lesions are thicker, more pronounced, and may extend beyond the hairline.
How can nail psoriasis be recognised?
Nail psoriasis may cause small pits on the nail surface, yellow-brown spots, separation of the nail from the nail bed, thickening, or cracking. One or several nails may be affected.
How is scalp psoriasis treated?
Treatment may include medicated shampoos containing coal tar, salicylic acid, or zinc pyrithione, as well as corticosteroid lotions or foams. In more severe cases, systemic medication or phototherapy may be recommended.
Psoriasis and vaccinations: Are they compatible?
Vaccination is usually assessed individually, especially if a patient is using immunosuppressants or biologic medications. In such cases, certain restrictions may apply to live vaccines. Decisions should be made in consultation with a treating specialist.
