Table of ContentsView AllTable of ContentsDiagnosing Plaque PsoriasisSelf-ChecksMedical HistoryPhysical ExaminationLabs and TestsDetermining SeverityDifferential DiagnosisSummaryNext in Plaque Psoriasis GuideChronic Plaque Psoriasis: Prescription Treatments and Home Remedies
Table of ContentsView All
View All
Table of Contents
Diagnosing Plaque Psoriasis
Self-Checks
Medical History
Physical Examination
Labs and Tests
Determining Severity
Differential Diagnosis
Summary
Next in Plaque Psoriasis Guide
In some cases, your provider may take a biopsy (small skin sample) and look at it under the microscope to verify your diagnosis and rule out other skin conditions. An accurate diagnosis guides your treatment and helps putplaque psoriasisinto remission.
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Adermatologisttypically diagnoses and treats plaque psoriasis. However, you may also need care from a rheumatologist because it is an autoimmune condition. A dermatologist treats the skin, while a rheumatologist treats the underlying autoimmune disease.
People will usually be able to recognize thesymptoms of psoriasis, such as:
You may have other symptoms with your psoriasis. For example, joint pain, thick and irregular nails, andblepharitis(eyelid inflammation) commonly develop.
Though you may recognize the signs, it’s important to see a healthcare provider for a definitive diagnosis rather than trying to diagnose and treat it yourself. It’s easy to mistake psoriasis for other skin conditions such aseczemaandallergic dermatitis, especially if it is your first outbreak. It’s also essential to gettreatmentthat can help put psoriasis into remission.
Plaque Psoriasis Healthcare Provider Discussion GuideGet our printable guide for your next healthcare provider’s appointment to help you ask the right questions.Download PDFEmail AddressSign UpThank you, {{form.email}}, for signing up.There was an error. Please try again.
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A medical history is an important part of the diagnostic process. It identifies your individual risks for plaque psoriasis and helps diagnose conditions that may co-occur with the disease. When taking your medical history during your appointment, your healthcare provider will want to know about:
Your healthcare provider will also want to know about any skin cleansers, detergents, or chemicals you may have been exposed to and whether you have persistent or worsening joint pain.
After completing your medical history, your provider learns about your symptoms. They may ask about how frequently you have flares, how long the condition stays in remission, and if you notice triggers or signs of other problems associated with plaque psoriasis.
The physical exam will mainly involve the visual and manual inspection of the skin lesions. The aim of the exam is to determine whether the physical characteristics of your condition are consistent with psoriasis. A healthcare provider will examine your skin either with the naked eye or adermatoscope, an adjustable magnifying glass with a light source.
In addition to the skin, your healthcare provider may look at the condition of your nails and check whether you have pain or inflammation in the hands, wrists, elbows, wrists, knees, ankles, and small joints of the feet. An eye exam may also be performed to see if the eyelids,conjunctiva, or corneas are affected.
In some cases, your healthcare provider may perform askin biopsyto definitively diagnose plaque psoriasis.A biopsy is performed underlocal anesthesiato numb the skin.
Your provider takes a small skin sample, typically using a skin punch (a rounded tool that removes a patch of skin), and views the sample under a microscope. This magnified view reveals characteristics of psoriatic skin cells. Unlike eczema or healthy skin cells, psoriatic skin cells are thickened and compressed (acanthotic).
Your provider may want to do a biopsy if you have unusual symptoms or they suspect a condition other than psoriasis. They may also do a biopsy after starting treatment if your symptoms don’t improve.
Once psoriasis has been diagnosed, your healthcare provider may want to classify the severity of your condition.
The scale most commonly used to do this is called thePsoriasis Area and Severity Index (PASI).It is considered the gold standard for clinical research and a valuable tool for monitoring people with severe and/or intractable (treatment-resistant) psoriasis.
While PASI lists redness as a measure, your psoriasis may be different, depending on your natural skin color. Plaques may appear purple, brown, or ashen gray on dark-skinned individuals.
Generally speaking, PASI is used for moderate to severe cases of plaque psoriasis and when you’re treated with biologic drugs such asHumira (adalimumab)or Cimzia (certolizumab pegol). The PASI measurements direct the appropriate treatment and track your response to therapy.
As part of the diagnosis, your healthcare provider will perform adifferential diagnosisto exclude all other possible causes. This is especially important since there are no lab or imaging tests to support a plaque psoriasis diagnosis.
The differential diagnosis begins during your physical exam. As your provider examines your skin, they look for signs of other types of psoriasis. While each has similar disease pathways, they have different characteristics and may have different treatment approaches as well. Among them:
Your healthcare provider will also consider other skin conditions that aremistaken for psoriasis,including:
Because other skin conditions can mimic psoriasis, misdiagnosis is not uncommon. If you’re unsure about a diagnosis or unable to find relief from a prescribed treatment, do not hesitate to ask for further investigation or to seek asecond opinion.
They may also run blood work and lab tests if they need to rule out other conditions that could cause your symptoms, like allergies. They might also do tests to determine if you have health conditions that often occur with plaque psoriasis.
13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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American Academy of Dermatology.Psoriasis: signs and symptoms.
American Academy of Ophthalmology.What is blepharitis?
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Furue, K.; Ito, T.; Tsuji, G. et al.Autoimmunity and autoimmune co‐morbidities in psoriasis.Immunology.2018;154(1):21-7. doi:10.1111/imm.12891Ogdie, A. and Weiss, P.The Epidemiology of Psoriatic Arthritis.Rheum Dis Clin North Am.2015 Nov;41(4):545-68. doi:10.1016/j.rdc.2015.07.001Weigle, N. and McBanem S.Psoriasis.Am Fam Physician. 2013 May 1;87(9):626-33.
Furue, K.; Ito, T.; Tsuji, G. et al.Autoimmunity and autoimmune co‐morbidities in psoriasis.Immunology.2018;154(1):21-7. doi:10.1111/imm.12891
Ogdie, A. and Weiss, P.The Epidemiology of Psoriatic Arthritis.Rheum Dis Clin North Am.2015 Nov;41(4):545-68. doi:10.1016/j.rdc.2015.07.001
Weigle, N. and McBanem S.Psoriasis.Am Fam Physician. 2013 May 1;87(9):626-33.
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