Psoriasis is a chronic, non-contagious, autoimmune disorder characterized by plaques of thick, scaly skin. Around 125 million people worldwide are currently affected by psoriasis, according to the World Psoriasis Day consortium. The characteristic plaque of psoriasis is caused by the excessive buildup of skin cells. The underlying pathophysiology of psoriasis involves a defective inflammatory response that causes an overactive skin production cycle. In the normal regulated production cycle of 28 days in skin cells, the deeper layers of the skin cells rise to the top as they develop until they die and get shed off. However, in psoriasis, the skin has an accelerated cell cycle and therefore overproduces skin cells. This overproduction is so rapid that the dead cells don’t fall off as it normally does. This leads to an overaccumulation of cells in the skin and causes red, flaky, crusty skin lesions with a scaly presentation. Psoriasis predominantly affects joints areas like elbows, and knees but can also affect the face, hand, neck, legs, and head (scalp).
Etiology of Psoriasis
The underlying etiology for psoriasis has as of yet not been clearly established. However, it is believed to be multifactorial in origin, with certain genetic predispositions and environmental factors. However, Psoriasis is found to be associated with:
Psoriasis is known to run in families, but an exact cause for it is not known.
Triggers of Psoriasis
Certain factors, like those listed below, can initiate a psoriatic attack:
- A recent throat infection: Like any other autoimmune disease, having an infection can cause the immune system to go into overdrive and cause more damage than good.
- Recent Skin Injury: A skin abrasion, cut, and even injections and sunburns can trigger a psoriatic attack
- Medications: Beta-blockers, anti-malarial drugs, and lithium.
- Stress: The effects of stress on the immune system may be the cause.
- Alcohol: The negative effects of alcohol on the body are many.
Types of Psoriasis
Psoriasis can range from a mild, scaly lesion to severe manifestations of the disease. It is classified into five different types as follows:
- Plaque Psoriasis: This is the most common type of psoriasis, also known as psoriasis Vulgaris. It forms red, inflamed patches covered by white-grey scales on knees, elbows, and scalp.
- Guttate Psoriasis: This mostly affects children, presenting with red, drop-like spots all over the torso, arms, and legs.
- Pustular Psoriasis: This type is also common in adults. It presents with red inflamed skin with whitish-yellow pus-filled blisters. It tends to affect hands and feet but it can be extended in its growth pattern.
- Inverse Psoriasis: This type usually develops in armpits or breasts, in the groin, or around skinfolds in the genitals with red, shiny, inflamed lesions.
- Erythrodermic Psoriasis: It is a rare form that involves lesions on the entire body surface, and is the most extreme type of psoriasis. Patients affected by EP are at higher risk for developing a fever, and Congestive Heart Failure if a heart condition already exists. This type can become fatal, immediate treatment is necessary.
Symptoms of Psoriasis
Symptoms of psoriasis differ from patient to patient, and they depend on the surface area affected by psoriasis and the type of psoriasis. Commonly seen symptoms of psoriasis are:
- Whitish-grey scales around red, inflamed patches
- Pruritus around the lesion
- Burning sensation around the lesion
- Thick, pitted nails (they may resemble fungal nail infections)
- Inflamed and painful joints
- Soreness around patches
Symptoms specific to each type are:
- Plaque Psoriasis: It develops at sites of high friction, scratching, or abrasions. It presents with the typical, diagnostic Auspitz Sign (Tiny spot of blood on the skin after peeling off white flakes). It also affects nails which may show pinpoint depressions and/or distal onycholysis (separation of the nail from nail bed due to large yellow-brown separations)
- Guttate Psoriasis: It presents with less than half an inch bumps and plaques on the skin that appear immediately after a sore throat.
- Pustular Psoriasis: Systemically ill patients, with or without fever, with fast-developing pus-filled plaques on the entire upper body.
- Inverse Psoriasis: This is often misdiagnosed as it affects mostly the genital region, and has flat plaques with minimal scaling.
- Erythrodermic Psoriasis: Medical emergency and patients present feeling ‘cold and chilly’
Symptoms appear for a week or so, and then disappear in a cyclic manner. Patients are said to be in remission between these attacks.
Diagnosis of Psoriasis
Diagnosis of psoriasis depends on a detailed physical exam, family history due to the genetic aspect of the disease, and microscopic examination of skin biopsy. Although characteristic signs seen in the physical examination can make the diagnosis easy, there is often a risk of misdiagnosis. It is important to examine the skin lesion carefully and then, perform a skin biopsy. Skin biopsy is vital to differentiate between eczematous dermatitis and psoriasis and to exclude other diagnoses if a physical examination is inconclusive.
Treatment of Psoriasis
Unfortunately, psoriasis has no cure. Aim of treatment is to reduce inflammation and stop bouts of flare-ups. Treatment options for psoriasis fall into three categories:
1. Topical Ointments: These are useful in the treatment of mild forms of psoriasis which affects less than 10% of the total body surface. However, sometimes a corticosteroid injection may be given to a psoriatic plaque resistant to topical therapy. Ointments are listed as follows:
- Topical corticosteroids
- Topical retinoids
- Vitamin D analogs
- Salicylic acid
2. Light Therapy: It is used for moderate to severe forms of psoriasis as in those with lesions affecting greater than 10% of the body surface. This therapy exposes psoriasis patients to UVA and UVB radiation which kills the overactive WBCs that cause the overgrowth of skin cells.
3. Systemic Therapy: Like Light therapy, systemic therapy is reserved for moderate to severe forms of psoriasis. This method of treatment is also reserved for patients with psoriatic arthritis, to prevent permanent joint damage
a. Non-Biological Treatment (given in form of tablets)
1. Acitretin: Retinoid that can decrease skin cell production which can help in psoriasis. It is only given if other forms of treatment mentioned above fail to bring about a change in the patient’s condition.
2.Cyclosporine: This medication is an immunosuppressant, that can help with an autoimmune disease like psoriasis
3. Methotrexate: Like cyclosporine, this is also an immunosuppressant medication.
b. Biological Treatment (given in form of injections)
1. Adalimumab (Humira), a TNF-alpha-blocking antibody
2. Adalimumab-adbm (Cyltezo)
3. Brodalumab (Siliq), a human antibody against interleukins
4. Certolizumab pegol (Cimzia), a TNF-alpha blocker
5. Etanercept (Enbrel), a TNF-alpha blocker
6. Etanercept-szzs (Erelzi), a biosimilar like Enbrel
7. Guselkumab (Tremfya), an antibody against interleukins
8. Infliximab (Remicade), a TNF-alpha blocker
9. Ixekizumab (Taltz), an antibody that binds to inflammation-causing proteins/interleukins
10. Risankizumab-rzaa (SKYRIZI), an antibody against interleukins
11. Secukinumab (Cosentyx), a human antibody against interleukins
12. Ustekinumab (Stelara), a human antibody against interleukins
Another systemic drug that is FDA approved for the treatment of psoriatic arthritis and plaque psoriasis is a PDE4 inhibitor and TNF alpha-blocker, called Apremilast, and it was proven to show great results.
It is important to note that all medications have side-effects and it is important to keep track of any weight loss or gain depression, or anxiety that may develop after starting treatment.
Psoriasis is one of the common skin conditions and affected individuals should try and prevent any triggers or stressors that may lead to a psoriatic attack. FDA has found many new drugs that can be used to treat psoriasis, however, it is important to observe the patients for any side-effects of the drugs. These drugs are extremely efficient in the treatment of psoriasis but have serious side-effects that need to be kept in check.
Also, it is important to remember that there is no cure for psoriasis. These treatments aim to prevent attacks and the exacerbation of these attacks.