Sections

Presentation

History

The typical history given by a patient with plaque psoriasis is relatively straightforward: patients report prominent itchy, red areas with increased skin scaling and peeling. Patients are particularly aware of lesions on the scalp and extensor surfaces. Patients typically are self-conscious about their lesions and commonly report using clothing to cover affected sites and avoiding potentially embarrassing social activities.

Patients commonly recognize that new lesions appear at sites of injury or trauma to the skin. This isomorphic phenomenon (Koebner reaction) typically occurs 7-14 days after the skin has been injured and has been found in 38-76% of patients with plaque psoriasis. In some patients, so-called reverse-Koebner reactions have also been noted in which preexisting psoriatic plaques actually clear after injury or trauma to the skin.

Patients may report that their disease worsens in the winter and improves in the summer.

Significant joint pain, stiffness, and deformity are reported in the 10-20% of patients with psoriasis who develop psoriatic arthritis.

Physical Examination

Several cardinal features of plaque psoriasis can be readily observed during the physical examination.

Plaques

Psoriasis manifests as elevated lesions that vary in size from one to several centimeters (see image below). The thickened epidermis, expanded dermal vascular compartment, and infiltrate of neutrophils and lymphocytes account for the psoriatic lesions being raised and easily palpable. The number of lesions may range from few to many at any given time.

Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

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The plaques are irregular to oval and are most often located on the scalp, trunk, and limbs, with a predilection for extensor surfaces such as the elbows and knees. Smaller plaques may coalesce into larger lesions, especially on the legs and sacral regions (see image below). Fissuring within plaques can occur when lesions are present over joint lines or on the palms and soles.

Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.

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Well-circumscribed margins

Psoriatic plaques are well defined and have sharply demarcated boundaries. Psoriatic plaques occasionally appear to be immediately encircled by a paler peripheral zone referred to as the halo or ring of Woronoff.

Red color

The color of psoriatic lesions is a very distinctive rich, full, red color. Lesions on the legs sometimes carry a blue or violaceous tint.

Scale

Psoriatic plaques typically have a dry, thin, silvery-white or micaceous scale; however, the amount and thickness of this scale is quite variable. Removing the scale reveals a smooth, red, glossy membrane with tiny punctate bleeding points. These points represent bleeding from enlarged dermal capillaries after removal of the overlying suprapapillary epithelium. This phenomenon is known as the Auspitz sign.

Symmetry

Psoriatic plaques tend to be symmetrically distributed over the body. Lesions typically have a high degree of uniformity with few morphologic differences between the two sides.

Pruritus

Pruritus, one of the main symptoms of plaque psoriasis, is quite variable in intensity but should not be ignored. Emotional instability (eg, high levels of anxiety, depression) that might be induced by the disease often manifests as an increased tendency to scratch.

Nail psoriasis

Nail changes are commonly observed in patients with plaque psoriasis. Nails may exhibit pitting, onycholysis, subungual hyperkeratosis, or the oil-drop sign. A proper assessment of any patient suspected of having psoriasis should include careful examination of the nails.

Psoriasis in children

Plaque psoriasis manifests slightly differently in children. Plaques are not as thick, and the lesions are less scaly. Psoriasis may often appear in the diaper region in infancy and in flexural areas in children. The disease more commonly affects the face in children compared with adults.

Inverse psoriasis

This is a variant of psoriasis that spares the typical extensor surfaces and affects intertriginous (ie, axillae, inguinal folds, inframammary creases) areas with minimal scale.

Psoriatic arthritis

Approximately 10-20% of all cases of plaque psoriasis are associated with psoriatic arthritis. Signs of psoriatic arthritis include the following:

Red, warm, tender, and inflamed joints
Joint deformity
Dactylitis
Sausage digits

Obesity

Patients with obesity and psoriasis may have an increased risk of cardiovascular disease. This association appears to be strongest in younger patients with severe disease and may be related to the metabolic syndrome.^[16]

Alcoholism

Alcoholism can be considered a complication of psoriasis. Male patients with severe disease are particularly at risk for this type of substance abuse.

Differential Diagnoses

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Armstrong AW, Gooderham M, Warren RB, Papp KA, Strober B, Thaçi D, et al. Deucravacitinib versus placebo and apremilast in moderate to severe plaque psoriasis: efficacy and safety results from the 52-week, randomized, double-blinded, placebo-controlled phase 3 POETYK PSO-1 trial. J Am Acad Dermatol. 2022 Jul 9. [QxMD MEDLINE Link]. [Full Text].
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Gordon KB, Strober B, Lebwohl M, Augustin M, Blauvelt A, Poulin Y, et al. Efficacy and safety of risankizumab in moderate-to-severe plaque psoriasis (UltIMMa-1 and UltIMMa-2): results from two double-blind, randomised, placebo-controlled and ustekinumab-controlled phase 3 trials. Lancet. 2018 Aug 25. 392 (10148):650-661. [QxMD MEDLINE Link].
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Sukal SA, Nadiminti L, Granstein RD. Etanercept and demyelinating disease in a patient with psoriasis. J Am Acad Dermatol. 2006 Jan. 54(1):160-4. [QxMD MEDLINE Link].
Wong VK, Lebwohl MG. Treatment of psoriatic arthritis with etanercept, a tumour necrosis factor antagonist. Expert Opin Biol Ther. 2005 Nov. 5(11):1505-13. [QxMD MEDLINE Link].
Paller AS, Siegfried EC, Eichenfield LF, Pariser D, Langley RG, Creamer K, et al. Long-term etanercept in pediatric patients with plaque psoriasis. J Am Acad Dermatol. 2010 Nov. 63(5):762-8. [QxMD MEDLINE Link].
Menter A, Gordon KB, Leonardi CL, Gu Y, Goldblum OM. Efficacy and safety of adalimumab across subgroups of patients with moderate to severe psoriasis. J Am Acad Dermatol. 2010 Sep. 63(3):448-56. [QxMD MEDLINE Link].
Langley RG, Feldman SR, Han C, Schenkel B, Szapary P, Hsu MC, et al. Ustekinumab significantly improves symptoms of anxiety, depression, and skin-related quality of life in patients with moderate-to-severe psoriasis: Results from a randomized, double-blind, placebo-controlled phase III trial. J Am Acad Dermatol. 2010 Sep. 63(3):457-65. [QxMD MEDLINE Link].
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Vender R, Lynde C, Gilbert M, Ho V, Sapra S, Poulin-Costello M. One-Year, Multicenter, Open-Label, Single-Arm Study Evaluating the Safety and Effectiveness of Etanercept for the Treatment of Moderate-to-Severe Plaque Psoriasis in a Canadian Population. J Cutan Med Surg. 2013 Mar-Apr. 17(2):129-38. [QxMD MEDLINE Link].
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Blauvelt A, Papp KA, Griffiths CE, Randazzo B, Wasfi Y, Shen YK, et al. Efficacy and safety of guselkumab, an anti-interleukin-23 monoclonal antibody, compared with adalimumab for the continuous treatment of patients with moderate to severe psoriasis: Results from the phase III, double-blinded, placebo- and active comparator-controlled VOYAGE 1 trial. J Am Acad Dermatol. 2017 Mar. 76 (3):405-417. [QxMD MEDLINE Link]. [Full Text].
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[Guideline] American Academy of Dermatology. Section 1. Overview of psoriasis and guidelines of carefor the treatment of psoriasis with biologics. Available at https://www.aad.org/File%20Library/Global%20navigation/Education%20and%20quality%20care/Guidelines-psoriarsis-sec-1.pdf. Accessed: October 11, 2017.
[Guideline] American Academy of Dermatology. Section 2. Psoriatic arthritis: Overview and guidelines of carefor treatment with an emphasis on the biologics. Available at https://www.aad.org/File%20Library/Global%20navigation/Education%20and%20quality%20care/Guidelines-psoriasis-sec-2.pdf. Accessed: October 11, 2017.
[Guideline] American Academy of Dermatology. Section 3. Guidelines of care for the management and treatmentof psoriasis with topical therapies. Available at https://www.aad.org/File%20Library/Global%20navigation/Education%20and%20quality%20care/Guidelines-psoriasis-sec-3.pdf. Accessed: October 11, 2017.
[Guideline] American Academy of Dermatology. Section 4. Guidelines of care for the management and treatment ofpsoriasis with traditional systemic agents. Available at https://www.aad.org/File%20Library/Global%20navigation/Education%20and%20quality%20care/Guidelines-psoriasis-sec-4.pdf. Accessed: October 11, 2017.
[Guideline] American Academy of Dermatology. Section 5. Guidelines of care for the treatment of psoriasis withphototherapy and photochemotherapy. Available at https://www.aad.org/File%20Library/Global%20navigation/Education%20and%20quality%20care/Guidelines-psoriasis-sec-5.pdf. Accessed: October 11, 2017.
[Guideline] American Academy of Dermatology. Section 6. Guidelines of care for the treatment of psoriasis and psoriatic arthritis: Case-based presentations and evidence-basedconclusions. Available at https://www.aad.org/File%20Library/Global%20navigation/Education%20and%20quality%20care/section6-psoriasis-guideline.pdf. Accessed: October 11, 2017.
[Guideline] Elmets CA, Korman NJ, Prater EF, et al. Joint AAD-NPF Guidelines of care for the management and treatment of psoriasis with topical therapy and alternative medicine modalities for psoriasis severity measures. J Am Acad Dermatol. 2021 Feb. 84 (2):432-470. [QxMD MEDLINE Link].
[Guideline] Smith CH, Jabbar-Lopez ZK, Yiu ZZ, Bale T, Burden AD, Coates LC, et al. British Association of Dermatologists guidelines for biologic therapy for psoriasis 2017. Br J Dermatol. 2017 Sep. 177 (3):628-636. [QxMD MEDLINE Link].
[Guideline] Menter A, Strober BE, Kaplan DH, et al. Joint AAD-NPF guidelines of care for the management and treatment of psoriasis with biologics. J Am Acad Dermatol. 2019 Feb 13. [QxMD MEDLINE Link].
[Guideline] Elmets CA, Lim HW, Stoff B, et al. Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis with phototherapy. J Am Acad Dermatol. 2019 Sep. 81 (3):775-804. [QxMD MEDLINE Link]. [Full Text].
Lebwohl MG, Stein Gold L, Strober B, Papp KA, Armstrong AW, Bagel J, et al. Phase 3 Trials of Tapinarof Cream for Plaque Psoriasis. N Engl J Med. 2021 Dec 9. 385 (24):2219-2229. [QxMD MEDLINE Link]. [Full Text].

Media Gallery

Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.
Plaque psoriasis. Courtesy of University of British Columbia, Department of Dermatology and Skin Science.
Plaque psoriasis. Photomicrograph of psoriasis. (1) Hyperkeratosis and parakeratosis, (2) neutrophils in the epidermis, (3) thinning of the epidermis overlying the dermal papillae, (4) vessels close to the epidermis, and (5) elongated rete ridges. Courtesy of Richard Crawford, MD, University of British Columbia, Department of Dermatology and Skin Science.

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Author

Harvey Lui, MD, FRCPC Professor and Head, Department of Dermatology and Skin Science, Vancouver General Hospital, University of British Columbia; Medical Director, The Skin Centre, Lions Laser Skin Centre and Psoriasis and Phototherapy Clinic, Vancouver General Hospital

Harvey Lui, MD, FRCPC is a member of the following medical societies: Canadian Medical Association, American Society for Photobiology, Photomedicine Society, European Academy of Dermatology and Venereology, National Psoriasis Foundation, Canadian Dermatology Association, College of Physicians and Surgeons of British Columbia, North American Hair Research Society, Canadian Dermatology Foundation, American Academy of Dermatology, American Society for Laser Medicine and Surgery

Disclosure: Received consulting fee from Astellas for review panel membership; Received consulting fee from Amgen/Wyeth for speaking and teaching; Received honoraria from LEO Pharma for speaking and teaching; Received grant/research funds from LEO Pharma for investigator; Received grant/research funds from Galderma for other.

Coauthor(s)

Adam J Mamelak, MD, FRCPC Attending Physician, Division of Dermatology, The Ottawa Hospital, University of Ottawa

Adam J Mamelak, MD, FRCPC is a member of the following medical societies: American Academy of Dermatology, American College of Mohs Surgery, American Society for Dermatologic Surgery, Canadian Dermatology Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Richard P Vinson, MD Assistant Clinical Professor, Department of Dermatology, Texas Tech University Health Sciences Center, Paul L Foster School of Medicine; Consulting Staff, Mountain View Dermatology, PA

Richard P Vinson, MD is a member of the following medical societies: American Academy of Dermatology, Texas Medical Association, Association of Military Dermatologists, Texas Dermatological Society

Disclosure: Nothing to disclose.

Christen M Mowad, MD Professor, Department of Dermatology, Geisinger Medical Center

Christen M Mowad, MD is a member of the following medical societies: Alpha Omega Alpha, Noah Worcester Dermatological Society, Pennsylvania Academy of Dermatology, American Academy of Dermatology, Phi Beta Kappa

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

Mark G Lebwohl, MD Chairman, Department of Dermatology, Mount Sinai School of Medicine

Mark G Lebwohl, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Received none from Amgen for consultant & investigator; Received none from Novartis for consultant & investigator; Received none from Pfizer for consultant & investigator; Received none from Celgene Corporation for consultant & investigator; Received none from Clinuvel for consultant & investigator; Received none from Eli Lilly & Co. for consultant & investigator; Received none from Janssen Ortho Biotech for consultant & investigator; Received none from LEO Pharmaceuticals for consultant & inves.