What is Psoriasis?


Psoriasis is a condition that causes your skin to grow faster than normal. Your immune system, which normally fights germs and diseases, mistakenly attacks healthy skin cells, causing them to build up and form thick, red patches covered with white scales. The cause of psoriasis isn’t known, but it runs in families and can be triggered by many things.


Topical corticosteroids

Topical corticosteroids are medicines that are put on the skin to reduce inflammation and irritation. They can be mild or strong and are available on prescription. Some examples are hydrocortisone and clobetasol. It’s important to read the patient information leaflet that came with your medication. It’ll have specific advice about using it.

They work by lowering the immune system, which helps to ease inflammation and redness and to help get rid of scaly patches. They can also reduce the risk of psoriasis flares. They can be applied once or twice daily, depending on the medicine and the body part. The National Psoriasis Foundation has a chart to guide how much of a topical corticosteroid to use for each body site.

It’s best to start with the least potent treatment and increase the strength of the medication as necessary. This will help avoid side effects such as thinning of the skin, easy bruising and a general feeling of tiredness (mood changes).

Topical steroids can be used alone or in combination with other treatments such as vitamin D analogs or tar. Emollients can also be helpful, especially for dry, itchy areas of the skin. They can be combined with phototherapy or taken as tablets. In more severe cases of limited disease, more potent topical medications such as betamethasone dipropionate or calcipotriene may be needed.

Biological treatments

Many patients with psoriasis can be effectively treated using topical agents, phototherapy, or systemic therapies including the glucocorticoid cyclosporine or methotrexate. Although high response rates are possible with these treatments, some patients cannot achieve or maintain acceptable levels of disease control. This may be due to factors such as drug tolerance, values and preferences regarding the desired level of disease control, or difficulties with adherence to treatment.

The development of new biologic immune modifying agents, such as the anti-tumor necrosis factor (TNF) agent adalimumab압구정피부과 , has increased the number of viable treatment options for patients with moderate to severe plaque psoriasis. These agents typically show excellent short-term and long-term efficacy and favorable tolerability profiles. Other options include the IL-12/23 inhibitors ustekinumab, secukinumab, and ixekizumab; the anti-IL-17 inhibitors brodalumab, guselkumab, and tildrakizumab; and the anti-IL-23 antibody itolizumab [12-13].

Other topical treatments that are useful for limited disease in patients with psoriasis include tar, which acts through the aryl hydrocarbon receptors and has apparent antiproliferative and anti-inflammatory effects, as well as keratolytic agents such as salicylic acid. Although tar can be applied directly to the skin, some patients find it messy and difficult to apply, which may negatively impact adherence. Another option is a topical solution, gel, lotion, or foam vehicle such as apremilast, which has been shown to improve adherence and efficacy when used for psoriasis.


Although psoriasis is usually diagnosed clinically, the doctor might need to take a small sample of your skin (biopsy) for examination under a microscope to confirm the diagnosis or rule out other disorders that can cause similar symptoms. A biopsy can help determine what kind of psoriasis you have, and how far the condition has spread.

The doctor will use a type of anesthesia to numb the area before performing a skin biopsy. Depending on the location, this may be local anesthesia, conscious sedation or general anesthesia. Once the anesthesia takes effect, most biopsies are painless.

Using a scalpel, the dermatologist will remove a small piece of the affected area and send it to a lab to be examined under a microscope. The results should be available in about a week.

In most cases, the histologic findings of psoriasis are characteristic with sharply demarcated scaly plaques with elongated ridges on the extensor surfaces of the body. This is an immune-mediated disorder characterized by hyperkeratosis, parakeratosis, acanthosis, dilated blood vessels and a lymphocytic infiltrate in the epidermis.

Psoriasis also causes nail changes, including pitting and splinting of the nails. Pitting is caused by the accumulation of excess keratin in the matrix of the nail plate, causing the cells to slough off prematurely. In the nail bed, psoriatic lesions may lead to leukonychia and onycholysis.

Other treatments

Other systemic treatments for psoriasis include methotrexate, cyclosporine, and the newer biologic agents. In general, the use of these agents is reserved for patients who are refractory to topical therapies and/or phototherapy. However, patients with limited disease are also candidates for systemic therapy.

Etanercept is a TNF-alpha inhibitor that is of benefit in psoriasis. It is a first-line therapy for patients with chronic moderate to severe plaque psoriasis and also is an effective treatment of psoriatic arthritis. Standard adult dosing is a subcutaneous injection of 50 mg twice weekly for three months, followed by 50 mg weekly maintenance dosing.

Systemic retinoids are of benefit in patients with pustular psoriasis and in patients with HIV-associated psoriasis. Acitretin is the retinoid of choice, although it is a potent teratogen and is not recommended in women who might become pregnant. The newer retinoids, including isotretinoin and adapalene, have similar efficacy to acitretin but are less teratogenic.

Guselkumab is a human IgG1 lambda monoclonal antibody that targets the p19 subunit of IL-23. It is of benefit in psoriasis by inhibiting IL-23 signaling. It is approved by the FDA for patients with severe psoriasis who have failed to respond to other therapies or phototherapy. The standard dose is 100 mg administered every other week by injection. A weight-based regimen is also available.