What Is Plaque Psoriasis?

Plaque psoriasis is the most common form of psoriasis, accounting for as many as 90% of all cases. It is an autoimmune disease in which skin cells rapidly build up, forming scales and dry, itchy patches that flake off.

While the underlying cause of the disease remains a mystery, there are factors that can often trigger or worsen an outbreak, including obesity, stress, and smoking. Symptoms can be difficult to manage, but there is an ever-widening range of drugs that can temper the immune response and provide significant relief.

Plaque Psoriasis Symptoms

Chronic plaque psoriasis, also known as psoriasis vulgaris, typically appears as raised patches of inflamed skin covered with silvery-white scales (plaques). The plaques are most commonly found on the elbows, knees, scalp, and back. Plaque psoriasis can also affect the nails, causing discoloration, pitting, and even detachment of the nail from the nail bed.

Plaque psoriasis symptoms can often worsen during an infection, when a person is stressed, or if the skin is injured. Certain drugs like beta blockers and nonsteroidal anti-inflammatory drugs (NSAIDs) can also trigger symptoms. Scratching only makes things worse, causing bleeding and a visible thickening of the affected skin.

Symptoms can come and go, often staying in remission for months and even years at a time before flaring up for no apparent reason. In some cases, the symptoms may be cyclic and even seasonal.

Causes

Scientists don't yet fully understand the mechanisms behind autoimmune diseases like plaque psoriasis, but they believe that a person's genetics play a central role. Around a third of people with psoriasis will have a family history of the disease and evidence of chromosomal mutations on specific locations of a gene (known as PSORS1 through PSORS9).

Other causes of plaque psoriasis have been suggested, including past infections or toxic exposure, but most are hypothetical at best.

Whatever the trigger, plaque psoriasis will effectively accelerate the speed by which skin cells are produced.

Because of this, new skin cells will accumulate faster than the old ones can be shed. At the same time, the blood vessels just beneath the skin will start to enlarge in response to the chronic inflammation, causing localized swelling and redness.

Diagnosis

Plaque psoriasis is most often diagnosed by the appearance of the skin. No special blood tests or diagnostic exams are usually needed.

However, a healthcare provider will want to differentiate it from other forms of psoriasis (such as guttate psoriasis, triggered by a streptococcal infection, or pustular psoriasis, characterized by pus-filled blisters), as well as skin disorders with similar features, such as:

• Cutaneous T-cell lymphoma
• Discoid eczema
• Pityriasis rosea
• Ringworm
• Seborrheic eczema

If the diagnosis is uncertain, a skin biopsy or scraping may be performed and sent to the lab for analysis.

Treatment

Aside from being uncomfortable, plaque psoriasis can be a distressing condition, sometimes undermining a person's confidence and sense of wellbeing. Luckily, the treatment of psoriasis has advanced considerably in recent years in tandem with an ever-widening understanding of immunology and autoimmunity.

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Current treatment options include:

• Topical corticosteroids, which can be used continuously but generally no longer than eight weeks (due to the risk of thinning skin)
• Phototherapy, in which artificial ultraviolet light is used to penetrate the skin and slow the growth of skin cells
• Non-biologic drugs like methotrexate and cyclosporin, which suppress the immune system as a whole
• New biologic drugs, such as Enbrel (etanercept), Humira (adalimumab), Remicade (infliximab), Stelara (ustekinumab), Sotyktu (deucravacitinib), and Taltz (ixikizumab), which suppress specific parts of the immune system
• Otezla (apremilast), which is approved to treat both psoriasis and psoriatic arthritis
• Vitamin D3 analogs, which appear to slow the production of skin cells
• Retinoids, chemical compounds related to vitamin A that regulate the production of skin cells

Coping

While plaque psoriasis can be frustrating and difficult to control, there are ways to cope with the disease as you and your healthcare provider search for a sustainable solution.

Chief among these is the reduction of stress. To this end, you need to find ways to not only alleviate stress in your life (such as with yoga or meditation) but to seek professional help if you have persistent or worsening symptoms of anxiety or depression.

Diet and exercise can also help relieve some of the inflammatory stress of obesity while improving a person's overall mood, strength, and appearance.

A Word From Verywell

Plaque psoriasis can often make sufferers feel isolated and self-conscious. If this is you, it is important to remember you are not alone and that there are literally millions of people out there experiencing the exact same things as you. 

Start by reaching out to others on Talk Psoriasis, a social media platform managed by the National Psoriasis Foundation. It's a great place to share information, seek advice, or find support from others like you.

While there is no quick fix for plaque psoriasis, with a little support and diligence, most people eventually get a handle on their symptoms and improve their overall quality of life.