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Psoriasis Learning Zone


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There are several main types of psoriasis, each presenting with different symptoms and characteristics. Clinical manifestations are well-known and usually recognised easily. A complete skin examination, including the nails and scalp, should be performed (National Psoriasis Foundation, 2019).

This section of the Psoriasis Learning Zone will guide you through the different types of psoriasis, as well as the common signs and symptoms (including nail symptoms) and delve into the different tests available to assess severity and response to treatment, including the impact of psoriasis on the patient’s quality of life.

Signs and symptoms

There are several main types of psoriasis, each presenting with different symptoms and characteristics. A psoriasis patient may present with more than one type, which may also change over time (National Psoriasis Foundation, 2019).


Signs and symptoms of psoriasis


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Diagnosis and severity assessment

Diagnosis of psoriasis is primarily on clinical grounds, based on examination of plaques or skin lesions with the characteristic silvery scales. Pathology, serology or imaging tests are usually not required (Cohen et al., 2012; Boehncke & Schön, 2015; Diani et al., 2015).


Psoriasis severity depends on a number of clinical factors and the disease is associated with a range of comorbidities and risk factors (Lubrano et al., 2015).


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Diagnosis and assessment references

Au SC, Madani A, Alhaddad M, Alkofide M, Gottlieb AB. Comparison of the efficacy of biologics versus conventional systemic therapies in the treatment of psoriasis at a comprehensive psoriasis care center. J Drugs Dermatol. 2013;12:861–6.

Bissonnette R, Tsai TF, Han C, Song M, Li S, McElligott S, et al. Benefits of achieving patient-reported symptom-free status vs PASI 100 response: Analysis from the VOYAGE 2 clinical trial. Presented at 27th European Academy of Dermatology and Venerology Congress, 12–16 September 2018. P1899.

Boehncke WH, Boehncke S. More than skin-deep: the many dimensions of psoriatic disease. Swiss Med Wkly. 2014;144:w13968.

Boehncke WH, Schön MP. Psoriasis. Lancet. 2015;pii: S0140-6736(14)61909–7.

Bonifati C, Berardesca E. Clinical outcome measures of psoriasis. Reumatismo. 2007;59 Suppl 1:64–7.

Buzney CD, Peterman C, Saraiya A, Au SC, Dumont N, Mansfield R, et al. Clearance of psoriasis: the impact of private versus public insurance. J Drugs Dermatol. 2015;14:119–25.

Chiesa Fuxench ZC, Callis Duffin K, Siegel M, Van Voorhees AS, Gelfand JM. Validity of the Simple-Measure for Assessing Psoriasis Activity (S-MAPA) for objectively evaluating disease severity in patients with plaque psoriasis. J Am Acad Dermatol. 2015;73:868–70.

Cohen SN, Baron SE, Archer CB. Guidance on the diagnosis and clinical management of psoriasis. Clin Experiment Dermatol. 2012;37(Suppl 1):13–8.

Diani M, Altomare G, Reali E. T-cell responses in psoriasis and psoriatic arthritis. Autoimmunity reviews. 2015;14:286–92.

Duffin KC, Papp KA, Bagel J, Levi E, Chen R, Gottlieb AB. Evaluation of the physician global assessment and body surface area composite tool for assessing psoriasis response to apremilast therapy: Results from ESTEEM 1 and ESTEEM 2. J Drugs Dermatol. 2017;16:147–153.

Feldman SR, Bushnell DM, Klekotka PA, Scanlon M, Martin ML, Wade SW, et al. Differences in psoriasis signs and symptom severity between patients with clear and almost clear skin in clinical practice. J Dermatolog Treat. 2015a;27(3):224–7.

Feldman SR, Krueger GG. Psoriasis assessment tools in clinical trials. Ann Rheum Dis. 2005;64 Suppl 2:ii65-8.

Gordon KB, Han C, Li S, You Y, Song M, Fakharzadeh S, et al. Clinician-reported PASI response versus patient-reported symptoms and signs among patients with moderate to severe psoriasis: results from the VOYAGE 1 & 2 clinical trials. Presented at 27th European Academy of Dermatology and Venerology Congress, 12–16 September 2018a. P2035.

Handa S. Newer trends in the management of psoriasis at difficult to treat locations: scalp, palmoplantar disease and nails. Indian J Dermatol Venereol Leprol. 2010;76(6):634–44.

Langley RG, Feldman SR, Nyirady J, van de Kerkhof P, Papavassilis C. The 5-point Investigator's Global Assessment (IGA) Scale: A modified tool for evaluating plaque psoriasis severity in clinical trials. J Dermatolog Treat. 2015a;26(1):23–31.

Lubrano E, Cantini F, Costanzo A, Girolomoni G, Prignano F, Olivieri I, et al.  Measuring psoriatic disease in clinical practice. An expert opinion position paper. Autoimmun Rev. 2015;14:864–74.

Manalo IF, Gilbert KE, Wu JJ. Time to Raise the Bar to Psoriasis Area Severity Index 90 and 100. J Drugs Dermatol. 2015;14:1086–8.

Mrowietz U, Kragballe K, Reich K, Spuls P, Griffiths CE, Nast A, et al. Definition of treatment goals for moderate to severe psoriasis: a European consensus. Arch Dermatol Res. 2011;303:1–10.

Nast A, Boehncke WH, Mrowietz U, Ockenfels HM, Philipp S, Reich K, et al. S3 - Guidelines on the treatment of psoriasis vulgaris (English version). Update. J Dtsch Dermatol Ges. 2012;10 Suppl 2:S1–95.

Nast A, Gisondi P, Ormerod AD, Saiag P, Smith C, Spuls PI, et al. European S3-Guidelines on the systemic treatment of psoriasis vulgaris--Update 2015--Short version--EDF in cooperation with EADV and IPC. J Eur Acad Dermatol Venereol. 2015;29(12):2277–94.

National Psoriasis Foundation. 2019. Available at (accessed September 2019).

Nestle FO, Kaplan DH, Barker J. Psoriasis. N Engl J Med. 2009;361:496–509.

Ngan V, Oakley A. Nail Psoriasis. DermnetNZ, February 2016. Available at (accessed September 2019).

Palfreeman AC, McNamee KE, McCann FE. New developments in the management of psoriasis and psoriatic arthritis: a focus on apremilast. Drug Des Devel Ther. 2013;7:201–10.

Pasch MC. Nail Psoriasis: A Review of Treatment Options. Drugs. 2016; 76:675–705.

Puig L, Thom H, Mollon P, Tian H, Ramakrishna GS. Clear or almost clear skin improves the quality of life in patients with moderate-to-severe psoriasis: a systematic review and meta-analysis. J Eur Acad Dermatol Venereol. 2017;31:213–20.

Reich K, Griffiths C, Lebwohl M, Nikai E, Edson-Heredia E, Lin CY, et al. Complete resolution of psoriasis is associated with greater improvements in itch and health-related quality of life: an anlalysis from UNCOVER-1, a phase 3 clinical trial of ixekizumab. EADV. Copenhagen, Denmark. 7–11 October, 2015a. P1642.

Robinson A, Kardos M, Kimball AB. Physician Global Assessment (PGA) and Psoriasis Area and Severity Index (PASI): why do both? A systematic analysis of randomized controlled trials of biologic agents for moderate to severe plaque psoriasis. J Am Acad Dermatol. 2012;66:369–75.

Sorensen EP, Fanucci KA, Saraiya A, Volf E, Au SC, Argobi Y, et al. Tumor necrosis factor inhibitor primary failure predicts decreased ustekinumab efficacy in psoriasis patients. J Drugs Dermatol. 2015;14:893–8.

Strober B, Papp KA, Lebwohl M, Reich K, Paul C, Blauvelt A, et al. Clinical meaningfulness of complete skin clearance in psoriasis. J Am Acad Dermatol. 2016a;75(1):77–82.

Torii H, Sato N, Yoshinari T, Nakagawa H; Japanese Infliximab Study Investigators. Dramatic impact of a Psoriasis Area and Severity Index 90 response on the quality of life in patients with psoriasis: an analysis of Japanese clinical trials of infliximab. J Dermatol. 2012;39(3):253–9.

Twelves S, Mostafa A, Dand N, Burri E, Farkas K, Wilson R, et al. Clinical and genetic differences between pustular psoriasis subtypes. J Allergy Clin Immunol. 2019;143(3):1021–1026.

Ventura A, Mazzeo M, Gaziano R, Galluzzo M, Bianchi L, Campione E. New insight into the pathogenesis of nail psoriasis and overview of treatment strategies. Drug Des Devel Ther. 2017;11:2527–35.

Walsh JA, Jones H, Mallbris L, Duffin KC, Krueger GG, Clegg DO, et al. The Physician Global Assessment and Body Surface Area composite tool is a simple alternative to the Psoriasis Area and Severity Index for assessment of psoriasis: post hoc analysis from PRISTINE and PRESTA. Psoriasis (Auckl). 2018;8:65–74.

Williamson L, Dalbeth N, Dockerty JL, Gee BC, Weatherall R, Wordsworth BP. Extended report: nail disease in psoriatic arthritis–clinically important, potentially treatable and often overlooked. Rheumatology March 2004;43(6):790–794.

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