Psoriasis – Diagnosis, Symptoms, and Treatment

Doctor Nathan LeDeaux, MD

Medically reviewed by Dr. Nathan LeDeaux, MD

Medical Professional

Updated - January 11, 2021

Nathan LeDeaux is an emergency medicine physician at the University of Wisconsin and got his M.D. from Northwestern University in Chicago Illinois.

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What is Psoriasis?

Psoriasis is an inflammatory skin condition that leads to the development of scaly plaques on the extensor surfaces of the body – the posterior neck, elbows, lower back, knees, and posterior ankles. While psoriasis is not a life-threatening condition it can lead to significant psychological distress due to its appearance. Browse our selection psoriasis medication available with prices up to 80% less than your local pharmacy.

Patients with severe cases may have diffuse involvement of the skin.  Flare-ups in these patients may be so severe that they require hospitalization at a burn center.  Psoriasis is also closely associated with cardiovascular disease – it is considered a predictor of coronary artery disease similar to other more common risk factors such as smoking, hypertension, and diabetes.

What Causes Psoriasis?

Psoriasis is an inflammatory skin disorder that is thought to be caused by a combination of genetic and environmental factors.  The most common risk factors for psoriasis include:

  • Family history
  • Smoking
  • Obesity
  • Infections – HIV
  • Alcohol use
  • Vitamin D deficiency

Patients living with psoriasis may experience flares rerouted to numerous lifestyle related factors. These triggers are very personal and what triggers flares in one person will not in another. The most common triggers that lead to psoriasis flares are:

  • Increased stress
  • Skin injury
  • Excessive alcohol intake
  • Dry and cold winter weather
  • Excessive sunshine

How Common is Psoriasis?

Psoriasis is relatively common, over 7.5 million Americans in the United States are estimated to be living with psoriasis. This condition is more common in adults than it is in children and adolescents. It is also more common in those of Caucasian descent. An estimated 3.6% of Caucasians are living with psoriasis, 1.9% of African Americans, and 1.6% of Hispanic individuals. 

Signs and Symptoms

Psoriasis typically presents with a classic silvery, scaly rash in the extensor regions of the body such as the back of the head, neck, elbows, knees, low back, and posterior ankles.  The rash can be cosmetically displeasing and may occasionally be itchy and painful.  There are various other appearances and forms of psoriasis including guttate psoriasis, pustular psoriasis, and erythrodermic psoriasis that are beyond the scope of this article.

The area of damaged skin may bleed and can become infected by bacteria – resulting in cellulitis, infection and inflammation of the skinPatients with cellulitis generally have redness, warmth, pain, and swelling spreading from the area of infection on the skin.  Patients with severe psoriasis may have a diffuse rash involving the whole body.  These patients are often managed as burn patients and often require specialty care and hospital admission.

Psoriatic arthritis is a form of psoriasis that is characterized by involvement of the joints in the body in addition to the aforementioned skin findings. The most common features of psoriatic arthritis are:

  • Sausage digits – swollen fingers and toes
  • Low back pain – sacroiliitis
  • Pitting of fingernails

Joint pain is typically worse in the first hour of waking and improves throughout the day.  Joints often become red, swollen, and tender. These arthritis symptoms tend to increase in severity with flares of skin disease


The diagnosis of psoriasis is generally made based on your history of symptoms and a basic physical exam alone. If your skin changes do not respond to medication, are atypical for psoriasis, or you have complications such as arthritis, severe disease, or a large area of affected skin more aggressive testing will be preformed. 

Patients with widespread skin involvement or systemic symptoms or signs often warrant blood tests such as a CMP (comprehensive metabolic panel), CBC (complete blood cell count), and inflammatory markers (ESR/CRP).  They will also usually check your cholesterol levels and screen for diabetes due to the increased cardiovascular risk that is seen in patients with psoriasis. In atypical cases, your doctor may refer you to a dermatologist for a definitive diagnosis with skin biopsy.


Psoriasis Medication and Treatment

The treatments that are used for psoriasis vary based on its severity and the presence of any complications. Some patients with very mild disease will not respond to treatment and may require additional medications that normally would not be used for mild psoriasis.

Mild cases of psoriasis are typically treated with phototherapy and topical corticosteroid creams or ointments such as:

Alternatives to topical corticosteroids may include topical tar, retinoids (tazarotene), and vitamin D.  Topical tacrolimus or pimecrolimus may also be considered for use on the face or intertriginous areas (areas where the skin rubs together).

Systemic agents such as retinoids, methotrexate, and cyclosporine are sometimes considered in patients with moderate to severe disease that does not respond to the aforementioned treatments

Biologic agents are a new class of medications that may be beneficial in patients with severe or extremely treatment resistant psoriasis. These medications have a much greater risk of side effects than traditional psoriasis treatments. The most commonly prescribed agents include:

  • Humira (adalimumab)
  • Enbrel (etanercept)
  • Remicade (infliximab)

Patients with psoriasis of any severity often benefit from the use of emollients over the skin such as Aquaphor.  These topical moisturizers help promote tissue healing by preventing excessive dehydration of the skin and reducing the sensation of itching.

Patients with bacterial infection resulting in cellulitis typically require treatment with oral antibiotics.  The most commonly prescribed antimicrobial therapy for cellulitis include:

  • Keflex (cephalexin)
  • Augmentin (amoxicillin-clavulanate)
  • Ancef (cefazolin)
  • Tetracycline (doxycycline)
  • Bactrim (trimethoprim-sulfamethoxazole)
  • Clindamycin

Severe cases of cellulitis may require intravenous antibiotics such as Vancomycin and Zosyn (piperacillin-tazobactam). This is more common if the infection spreads to other areas of the skin in patients with severe psoriasis that covers large areas of skin.



  1. Armstrong AW, Robertson AD, Wu J, et al. Undertreatment, treatment trends, and treatment dissatisfaction among patients with psoriasis and psoriatic arthritis in the United States: findings from the National Psoriasis Foundation surveys, 2003-2011. JAMA Dermatol 2013; 149:1180. -
  2. Samarasekera EJ, Sawyer L, Wonderling D, et al. Topical therapies for the treatment of plaque psoriasis: systematic review and network meta-analyses. Br J Dermatol 2013; 168:954. -

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.