Fact Explanation
Skin lesions Psoriasis is a non-infective, chronic inflammatory condition of the skin characterized by an erythematous scaly eruption.[1] Skin lesions are usually non-itchy. The skin lesions have a predilection to involve the extensor surfaces and the scalp. The presenting skin lesion will differ according to the subtype. Common subtypes include stable plaque psoriasis, Guttate psoriasis, flexural psoriasis, palmoplantar psoriasis, pustular psoriasis and erythrodermic psoriasis.
Nail involvement The nails are involved commonly where the characteristic lesions are nail pitting, separation from the nail bed and hyperkeratosis under the nail.[2]
Psoriatic arthropathy Presentation is with pain and swelling of joints and entheses.[3] Large and small joints of both upper and lower limbs may be affected. Joint involvement may mimic both rheumatoid arthritis and ankylosing spondylitis.
Chronic fluctuating course The natural course of the disease is very variable.[4] Patients who develop the disease at an early age and those who have a severe initial presentation tend to have a more severe and long lasting course. The disease may flare up periodically due to precipitating factors.
Age of onset The disease has a bimodal presentation. Type 1 psoriasis develops in younger patients (teenagers & early adults) and have a strong family history. Type 2 psoriatics develop the disease in the sixth, seventh decade while they have little genetic background.[1]
Risk factors for disease precipitation Factors which can precipitate the disease are trauma, infection (beta-hemolytic streptococcal throat infections), UV light, stress and drugs (beta-blockers, anti-malarial agents, lithium etc).[5]
Assess disease severity and impact on life Severity indexes such as Psoriasis Area and Severity Index (PASI) can be used for this purpose.[6] Psoriasis has a major impact on all aspects of life. Scores such as Dermatology Life Quality Index (DLQI) can be used for this purpose.
  1. NESTLE FRANK O., KAPLAN DANIEL H., BARKER JONATHAN. Psoriasis. N Engl J Med [online] 2009 July, 361(5):496-509 [viewed 11 July 2014] Available from: doi:10.1056/NEJMra0804595
  2. JIARAVUTHISAN MM, SASSEVILLE D, VENDER RB, MURPHY F, MUHN CY. Psoriasis of the nail: anatomy, pathology, clinical presentation, and a review of the literature on therapy. J Am Acad Dermatol [online] 2007 Jul, 57(1):1-27 [viewed 11 July 2014] Available from: doi:10.1016/j.jaad.2005.07.073
  3. CANTINI F, NICCOLI L, NANNINI C, KALOUDI O, BERTONI M, CASSARà E. Psoriatic arthritis: a systematic review. Int J Rheum Dis [online] 2010 Oct, 13(4):300-17 [viewed 11 July 2014] Available from: doi:10.1111/j.1756-185X.2010.01540.x
  4. FARBER EM, NALL ML. The natural history of psoriasis in 5,600 patients. Dermatologica [online] 1974, 148(1):1-18 [viewed 11 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/4831963
  5. HUERTA C, RIVERO E, RODRíGUEZ LA. Incidence and risk factors for psoriasis in the general population. Arch Dermatol [online] 2007 Dec, 143(12):1559-65 [viewed 11 July 2014] Available from: doi:10.1001/archderm.143.12.1559
  6. LANGLEY RG, ELLIS CN. Evaluating psoriasis with Psoriasis Area and Severity Index, Psoriasis Global Assessment, and Lattice System Physician's Global Assessment. J Am Acad Dermatol [online] 2004 Oct, 51(4):563-9 [viewed 25 September 2014] Available from: doi:10.1016/j.jaad.2004.04.012


Fact Explanation
Chronic plaque psoriasis The commonest presentation. The patient develops well demarcated erythematous plaques with silvery scales.[1] The skin lesions show superficial bleeding points when scales are removed (Auspitz sign). Trauma to the skin will lead to development of lesions along the area of trauma (Koebner phenomenon). The skin rash mainly develops on the extensor surfaces – Elbow, ankle, shin etc. Psoriatic lesions may also develop on the scalp.[2]
Guttate psoriasis Small rain drop like papules and macules with scaling develop on the trunk and extremities.[3]
Flexural psoriasis Individual lesions are well demarcated erythematous, moist, non-scaly and numerous. The lesions predominantly affect the flexural areas such as axillae, groins & popliteal area.[4]
Palmo-planter psoriasis Confluent, erythematous, hyperkeratotic scaly plaques develop over the palms and soles.[5]
Pustular psoriasis Sterile pustules with surrounding erythema develop as a localized or generalized rash.[6] The pustules may confluence with each other. The patient is ill with fever, malaise and joint pain.
Erythrodermic psoriasis Diffuse involvement of more than 90% of the body surface. Skin lesions will be erythematous and scaly.[7]
Nail changes The typical nail changes are thimble pitting, onycholysis (separation of the nail from its nail bed) and subungual hyperkeratosis.[8]
Psoriatic arthropathy About 5-10% of patients with psoriasis develop a sero-negative inflammatory arthropathy. Joint involvement can be categorized into 5 patterns - Asymmetric inflammatory oligoarthritis, symmetrical polyarthritis, distal interphalangeal arthritis, psoriatic spondylitis and arthritis mutilans.[9] Asymmetric inflammatory oligoarthritis is the commonest presentation. Involvement of the small joints with tenosynovitis, enthesitis in the hands and feet lead to the development of ‘sausage digit’ or dactylitis. In arthritis mutilans there is destruction of joint and cartilage of the fingers and toes. On examination the fingers may appear short, mutilated and crippled. This leads to encasing and invagination of the skin (‘telescoped’).
  1. NESTLE FRANK O., KAPLAN DANIEL H., BARKER JONATHAN. Psoriasis. N Engl J Med [online] 2009 July, 361(5):496-509 [viewed 11 July 2014] Available from: doi:10.1056/NEJMra0804595
  2. VAN DE KERKHOF PC, FRANSSEN ME. Psoriasis of the scalp. Diagnosis and management. Am J Clin Dermatol [online] 2001, 2(3):159-65 [viewed 11 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/11705093
  3. KO HC, JWA SW, SONG M, KIM MB, KWON KS. Clinical course of guttate psoriasis: long-term follow-up study. J Dermatol [online] 2010 Oct, 37(10):894-9 [viewed 26 September 2014] Available from: doi:10.1111/j.1346-8138.2010.00871.x
  4. VAN DE KERKHOF PC, MURPHY GM, AUSTAD J, LJUNGBERG A, CAMBAZARD F, DUVOLD LB. Psoriasis of the face and flexures. J Dermatolog Treat [online] 2007, 18(6):351-60 [viewed 26 September 2014] Available from: doi:10.1080/09546630701341949
  5. FARLEY E, MASROUR S, MCKEY J, MENTER A. Palmoplantar psoriasis: a phenotypical and clinical review with introduction of a new quality-of-life assessment tool. J Am Acad Dermatol [online] 2009 Jun, 60(6):1024-31 [viewed 26 September 2014] Available from: doi:10.1016/j.jaad.2008.11.910
  6. ZELICKSON BD, MULLER SA. Generalized pustular psoriasis. A review of 63 cases. Arch Dermatol [online] 1991 Sep, 127(9):1339-45 [viewed 26 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/1892402
  7. LANGLEY R G B. Psoriasis: epidemiology, clinical features, and quality of life. Annals of the Rheumatic Diseases [online] 2005 March, 64(suppl_2):ii18-ii23 [viewed 11 July 2014] Available from: doi:10.1136/ard.2004.033217
  8. TAN ES, CHONG WS, TEY HL. Nail psoriasis: a review. Am J Clin Dermatol [online] 2012 Dec 1, 13(6):375-88 [viewed 25 September 2014] Available from: doi:10.2165/11597000-000000000-00000
  9. GLADMAN D D. Psoriatic arthritis: epidemiology, clinical features, course, and outcome. Annals of the Rheumatic Diseases [online] 2005 March, 64(suppl_2):ii14-ii17 [viewed 11 July 2014] Available from: doi:10.1136/ard.2004.032482

Differential Diagnoses

Fact Explanation
Pityriasis Rosea Pityriasis Rosea is a papulosquamous skin disease. It is a self limiting condition, the aetiological agent is unknown.[1] The disease initially manifests with an erythematous scaly well demarcated oval shaped lesion which is seen in the anterior chest, back, neck or abdomen. This lesion is called the Herald patch and is present in about 50% of patients. This is followed by widespread discrete oval scaly plaques. The scales are fine and attached only to the periphery of the lesion (Colorate scales). The distribution of the skin rash is particularly along the ribs giving a christmas tree like appearance. The lesions may itchy. There are no systemic symptoms. Diagnosis of the condition is clinical while biopsy may aid in diagnostic difficulty. The disease usually resolves on its own which may take 4-6 weeks.
Lichen Planus Lichen planus is another papulosquamous disease which usually presents in the 4th decade of life. The aetiology is unknown while autoimmune mechanisms are considered to play a major role. Typical lesions are small violaceous flat topped papules. These may coalesce and form patches. The shapes of the skin lesions are polygonal while the surface has the characteristic Wickham striae – A lacy network of fine white lines.[2] The lesions are intensely itchy while koebner phenomenon is positive. The patient may develop mucosal lesions over the buccal mucosa & tongue. Oral lesions may not show the typical papules but Wickham striae are larger and easily visible. Nail involvement is a valuable diagnostic tool. Characteristic features are thin nail plates, horizontal ridges, onycholysis and darkening of the nails.
Discoid eczema Eczema or dermatitis can be acute/ chronic and develops due to endogenous (Atopic, seborrhoeic) or exogenous (Allergic, irritant, photoallergic) factors.[3] Among various morphologic patterns, Discoid eczema is a common presentation. Any chronic itchy condition may predispose to this disease. The patient presents with discrete discoid shaped eczematous lesions. There is intense pruritus. Skin lesions are mainly distributed on the limbs. Diagnosis is based on clinical information.
  1. NILES HENRY D.. PITYRIASIS ROSEA. Arch Derm Syphilol [online] 1940 February [viewed 11 July 2014] Available from: doi:10.1001/archderm.1940.01490080074005
  2. LE CLEACH LAURENCE, CHOSIDOW OLIVIER. Lichen Planus. N Engl J Med [online] 2012 February, 366(8):723-732 [viewed 11 July 2014] Available from: doi:10.1056/NEJMcp1103641
  3. PEATE I. Eczema: causes, symptoms and treatment in the community. Br J Community Nurs [online] 2011 Jul, 16(7):324, 326-31 [viewed 11 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/21727789

Investigations - for Diagnosis

Fact Explanation
Diagnosis is usually clinical Diagnosis of the condition is usually by identification of the typical rash and nail changes.[1]
Skin biopsy May be rarely indicated if the diagnosis is doubtful. Histological features on biopsy : Thickened epidermis, enlarged rete ridges, loss of the granular layer and increased mitotic activity of basal keratinocytes. Features of inflammation will be seen in the epidermis and dermis.Skin biopsy features can be compared before and after therapy.[2]
Nail biopsy Histopathological examination of nail samples may aid in the diagnosis when skin lesions are not prominent.[1] Histological findings : hyperkeratosis, epidermal hyperplasia & hypergranulosis.
Throat swab A throat swab for identification of Streptococcal infection may be required in Guttate psoriasis.[3]
  1. GROVER C, REDDY BS, UMA CHATURVEDI K. Diagnosis of nail psoriasis: importance of biopsy and histopathology. Br J Dermatol [online] 2005 Dec, 153(6):1153-8 [viewed 11 July 2014] Available from: doi:10.1111/j.1365-2133.2005.06862.x
  2. WERNER B, BRESCH M, BRENNER FM, LIMA HC. Comparative study of histopathological and immunohistochemical findings in skin biopsies from patients with psoriasis before and after treatment with acitretin. J Cutan Pathol [online] 2008 Mar, 35(3):302-10 [viewed 25 September 2014] Available from: doi:10.1111/j.1600-0560.2007.00800.x
  3. TELFER NR, CHALMERS RJ, WHALE K, COLMAN G. The role of streptococcal infection in the initiation of guttate psoriasis. Arch Dermatol [online] 1992 Jan, 128(1):39-42 [viewed 11 July 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/1739285

Investigations - Screening/Staging

Fact Explanation
Plasma glucose Psoriasis is associated with increased insulin resistance and cardiovascular risk.[1]
Lipid profile Psoriasis is associated with metabolic syndrome. Screen for cardiovascular risk factors.[1]
HIV testing HIV screening may be considered in severe and recurrent disease.[2]
  1. BOEHNCKE S, THACI D, BESCHMANN H, LUDWIG RJ, ACKERMANN H, BADENHOOP K, BOEHNCKE WH. Psoriasis patients show signs of insulin resistance. Br J Dermatol [online] 2007 Dec, 157(6):1249-51 [viewed 11 July 2014] Available from: doi:10.1111/j.1365-2133.2007.08190.x
  2. MORAR N, WILLIS-OWEN SA, MAURER T, BUNKER CB. HIV-associated psoriasis: pathogenesis, clinical features, and management. Lancet Infect Dis [online] 2010 Jul, 10(7):470-8 [viewed 11 July 2014] Available from: doi:10.1016/S1473-3099(10)70101-8

Management - General Measures

Fact Explanation
Patient education & counseling Discuss with the patient on the natural history of disease and non-infective nature, chronicity, precipitating factors and aetiology of disease. Information should be provided on the treatment options available. Psoriasis has a major impact on all aspects of life. Council the patient on occupation related problems, sexual relationship, stress management, leisure and personal relationships. Due to the chronicity of the disease treatment regimes should be practical and meet patient wishes and requirements. It is important to empower the patient with his/her own management.[1] Ensure good compliance to treatment.
Setting of management Patients with uncomplicated stable psoriasis and psoriasis involving <60% of total body surface can be managed at home under the supervision of a general practitioner. Patients presenting with pustular psoriasis or erythrodermic psoriasis need hospital based care. Psoriatic patients in special circumstances – pregnancy, concurrent HIV infection etc also need hospital based care.[2]
Psychological support Patients with psoriasis need psychological support and help to build their self esteem. Psoriatic patients have a significant risk of developing depression, anxiety and suicidal ideas.[3] [4]
Diet Protein is lost via the scales that break off. Hence patient should be advised to consume a high protein diet.[2]
Advise the patient on increased cardiovascular risk Existing cardiovascular risk factors such as diabetes, hypertension and hyperlipidaemia should be addressed with appropriate pharmacological and non-pharmacological management - smoking cessation, adequate exercise, healthy diet and maintenance of appropriate body mass index.[5]
  1. STERN ROBERT S., NIJSTEN TAMAR, FELDMAN STEVEN R., MARGOLIS DAVID J., ROLSTAD TARA. Psoriasis Is Common, Carries a Substantial Burden Even When Not Extensive, and Is Associated with Widespread Treatment Dissatisfaction. J Invest Dermat SP [online] 2004 March, 9(2):136-139 [viewed 11 July 2014] Available from: doi:10.1046/j.1087-0024.2003.09102.x
  2. MENTER A, KORMAN NJ, ELMETS CA, FELDMAN SR, GELFAND JM, GORDON KB, GOTTLIEB A, KOO JY, LEBWOHL M, LIM HW, VAN VOORHEES AS, BEUTNER KR, BHUSHAN R, AMERICAN ACADEMY OF DERMATOLOGY. Guidelines of care for the management of psoriasis and psoriatic arthritis. Section 3. Guidelines of care for the management and treatment of psoriasis with topical therapies. J Am Acad Dermatol [online] 2009 Apr, 60(4):643-59 [viewed 25 September 2014] Available from: doi:10.1016/j.jaad.2008.12.032
  3. KURD SK, TROXEL AB, CRITS-CHRISTOPH P, GELFAND JM. The risk of depression, anxiety, and suicidality in patients with psoriasis: a population-based cohort study. Arch Dermatol [online] 2010 Aug, 146(8):891-5 [viewed 11 July 2014] Available from: doi:10.1001/archdermatol.2010.186
  4. ESPOSITO M, SARACENO R, GIUNTA A, MACCARONE M, CHIMENTI S. An Italian study on psoriasis and depression. Dermatology [online] 2006, 212(2):123-7 [viewed 11 July 2014] Available from: doi:10.1159/000090652
  5. BOEHNCKE W.-H., BOEHNCKE S., SCHON M. P. Managing comorbid disease in patients with psoriasis. BMJ [online] December, 340(jan15 1):b5666-b5666 [viewed 11 July 2014] Available from: doi:10.1136/bmj.b5666

Management - Specific Treatments

Fact Explanation
Treatment options Both topical and systemic treatment options are available. Systemic therapy options include Retinoids, Immunosuppressants (methotrexate, cyclosporine, mycophenolate), Immunomodulators ( fumaric acid esters), Biological immunosuppressants (infliximab).[1] Drugs should be administered in a stepwise progression. There is limited evidence for multiple drug regimes.[2]
Topical treatments The patient is started on topical treatments initially as first line therapy.[3] Topical treatments : coal tar, dithranol, steroids, calcipotriol, emollients.
Ultraviolet radiation (UVR) treatments such as ultraviolet B (UVB) and psoralen–ultraviolet A (PUVA) UVR is used as a second line therapy if topical treatment options are ineffective.[4] Phototherapy slows the rapid growth/ proliferation of new skin cells.
Systemic retinoids or immunosuppressants If the patient fails to respond or early recurrences occur, therapy with systemic retinoids or immunosuppressants may be considered as third line therapy. Acitretin is the commonly used retinoid. Methotrexate is the first line immune-suppressant used, followed by cyclosporine, mycophenolate mofetil and hydroxycarbamide etc.[5]
Immunomodulators and Biological immunosuppressants If the patient fails to respond to to retinoids and immunosuppressants these agents may be used - fumaric acid esters or biological agents(infliximab).[6]
Monitor for adverse drug reactions Drugs used have various side effect profiles. Monitor for side effects of immunosuppressants such as bone marrow suppression, hepatotoxicity, lung fibrosis, renal dysfunction etc. Some drugs have teratogenic properties.[2]
Rheumatology assessment and management Patients with psoriatic arthropathy should be referred to a rheumatologist for assessment and management. For mild disease symptomatic control with NSAIDs and other analgesics is sufficient. Intra-articular steroids may be used for severe joint inflammation. Patients who are resistant to conservative treatment can be started on DMARDs and anti-TNF agents. Exercise and physiotherapy is encouraged. Retinoid acitretin, photo-chemotherapy and psoralen ultraviolet light is effective for both skin lesions and arthritis.[7]
  1. WEGER W. Current status and new developments in the treatment of psoriasis and psoriatic arthritis with biological agents. Br J Pharmacol [online] 2010 Jun, 160(4):810-20 [viewed 11 July 2014] Available from: doi:10.1111/j.1476-5381.2010.00702.x
  2. FERENCE ELISABETH H.. Combination Treatments for Psoriasis. Arch Dermatol [online] 2012 April [viewed 11 July 2014] Available from: doi:10.1001/archdermatol.2011.1916
  3. SAMARASEKERA EJ, SAWYER L, WONDERLING D, TUCKER R, SMITH CH. Topical therapies for the treatment of plaque psoriasis: systematic review and network meta-analyses. Br J Dermatol [online] 2013 May, 168(5):954-67 [viewed 11 July 2014] Available from: doi:10.1111/bjd.12276
  4. LEBWOHL M, ALI S. Treatment of psoriasis. Part 1. Topical therapy and phototherapy. J Am Acad Dermatol [online] 2001 Oct, 45(4):487-98; quiz 499-502 [viewed 11 July 2014] Available from: doi:10.1067/mjd.2001.117046
  5. MENTER A, GRIFFITHS CE. Current and future management of psoriasis. Lancet [online] 2007 Jul 21, 370(9583):272-84 [viewed 11 July 2014] Available from: doi:10.1016/S0140-6736(07)61129-5
  6. THAPPA DM, LAXMISHA C. Immunomodulators in the treatment of psoriasis. Indian J Dermatol Venereol Leprol [online] 2004 Jan-Feb, 70(1):1-9 [viewed 25 September 2014] Available from: http://www.ncbi.nlm.nih.gov/pubmed/17642548
  7. RITCHLIN CT, KAVANAUGH A, GLADMAN DD, MEASE PJ, HELLIWELL P, BOEHNCKE WH, DE VLAM K, FIORENTINO D, FITZGERALD O, GOTTLIEB AB, MCHUGH NJ, NASH P, QURESHI AA, SORIANO ER, TAYLOR WJ, FOR THE GROUP FOR RESEARCH AND ASSESSMENT OF PSORIASIS AND PSORIATIC ARTHRITIS (GRAPPA). Treatment recommendations for psoriatic arthritis Ann Rheum Dis [online] 2009 Sep, 68(9):1387-1394 [viewed 25 September 2014] Available from: doi:10.1136/ard.2008.094946