PSORIASIS
Dan Tsvine, MD
August 1, 2005
Psoriasis is a common chronic skin disorder typically characterized by erythematous papules and
plaques with a silver scale, although other presentations occur. Most patients are treated in the
outpatient setting.
Epidemiology
 Worldwide psoriasis prevalence rates range from 0.6 percent to 4.8 percent. A
population-based study in the United States estimated that the prevalence of psoriasis
was 2.5 percent in Caucasians and 1.3 percent in African-Americans. Approximately 1%
of population of North America affected; highest incidence in Scandinavia.
 Genetics: 40% of patients with arthritis have family history in first degree relative, and
psoriatic arthritis is 100x more likely to occur among family members than unrelated
controls. Finally psoriasis tends to be concordant among MZ twins more commonly than
among DZ twins.
Pathophysiology
 Incompletely understood, but felt to be immune-mediated disease based on findings of
inflammatory cell infiltrates in the dermis and epidermis, increased levels of TGF- in
psoriatic skin, evidence of activation of other cytokines (IL-2, IL-6, IL-8, -interferon), and
response to immunosuppressive agents.
 immune regulation of psoriasis is further supported by observations in patients receiving
bone marrow transplantations, with some individuals undergoing complete resolution of
psoriasis following translpants.
 Histopathologic characteristics include hyperproliferation and abnormal differentiation of
epidermis, inflammatory cell infiltrates in dermis and epidermis, and vascular
enlargement.
Types of Psoriasis
 Plaque Psoriasis (Psoriasis Vulgaris)
 Most common form – accounting for 90% of cases.
 Frequently presents in young adulthood, although any age may be affected.
 Lesions:
 Symmetrically distributed plaques involving the scalp, extensor surfaces of the
elbows, knees, and back. Plaques 1-10 cm in diameter with raised, well-defined
margins.
 Thick silvery scale frequently present (although bathing may remove scale).
 Classically asymptomatic, although some patients report pruritis, irritation, or
pain.
 Pitting of nail plates and involvement of intertriginous areas (umbilicus and
intergluteal cleft) may occur.
 Exacerbating factors: drugs (lithium, beta-blockers, anti-malarials, NSAIDs, ACEi,
terbinafine), infections (bacterial and viral), EtOH abuse.
 Diagnosis primarily clinical – based on historical and physical exam features. Biopsy
advised only when exam insufficient to make diagnosis. Biopsy at least 4 mm
diameter from middle of plaque or patch.
 Clinical course: Typically life-long, marked by variability in symptom severity over
time. However, prolonged remissions occur in 25% of patients.
 Guttate Psoriasis
 Abrupt onset of multiple small psoriatic lesions
 Most commonly affects children and young adults with no previous hx of psoriasis,
although patients with pre-existing plaque psoriasis may have guttate psoriatic flare.
 Acute onset in association with streptococcal infections, usually pharyngitis (reported
in 50% of cases), other infectious illnesses, injury, and stress.
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Lesions: Small (usually < 1cm) erythematous plaques with thin scale. Trunk and
limbs most often affected. May resolve spontaneously without recurrence, may recur
as guttate flares, or may recur as plaque psoriasis.
Inverse Psoriasis (aka Flexural Psoriasis)
 Commonly affects obese adults.
 Lesions: Smooth, dry, erythematous regions with scale. Affects intertriginous areas
– axillary, inguinal, inframammary, genital, intergluteal, and perineal – the “inverse” of
the typical presentation of plaque psoriasis on the extensor surfaces. No visible
scaling.
 Often misdiagnosed as fungal or bacterial infection.
Localized Pustular Psoriasis
 Manifestations confined to local areas – most often hands and feet.
 Onset usually at 20-60 years of age, with female predominance.
 Lesions: Small, sterile pustules (approximately ½ cm in diameter) on fleshy areas of
hands and feet. Cyclical course classically described, with new crops of pustules
followed by periods of low activity.
Generalized Pustular Psoriasis
 Generalized (von Zombusch variant) of pustular psoriasis is rare by may be severe.
 Abrupt onset. May be triggered by infection, withdrawal of systemic corticosteroids,
pregnancy, or drugs. Potentially complicated by hypovolemia, hypotension,
tachycardia, fever, hypoalbuminemia, fever.
 Lesions: Widespread erythroderma with sterile pustules. Pustules appear in cycles
lasting several days, followed by exfoliation, leaving the skin glazed and smooth.
 Demostrated hepatic abnormalities associated with this variant.
Erythrodermic Psoriasis
 Least common form, but also potentially most severe.
 More frequently affects patients with “unstable” plaque psoriasis – lesions that are not
clearly defined.
 Lesions: Widespread erythroderma, often with intense pruritis or pain.
Erythrodermic phase followed by exfoliation. May affect most of body surface and be
associated with hypovolemia, tachycardia, hypotension, electrolyte abnormalities,
hypoalbuminemia, superinfection, high output heart failure, capillary leak syndrome,
and ARDS.
 Precipitating factors include withdrawal of steroids or immunosuppressive agents,
severe sunburn, phototherapy burns, adverse reaction to topical or systemic
medication, pregnancy, infection, and emotional stress.
Nail Psoriasis
 Rarely isolated disease, but more often accompanies other manifestations of
psoriasis.
 Lesions: Few to multiple tiny pits over nail plate, reflecting abnormal nail plate growth
due to psoriatic involvement of nail matrix. These changes produce friable areas of
cornified nail plate that erone away with normal friction. Localized tan-brown color
change (“oil-drop” sign) is commonly described.
 More severe involvement marked by thickening and crumbling of nails – and easily
confused with onychomycosis.
 Unresponsive to most treatments.
Psoriatic Arthritis
 Occurs in up to 25% of patients with psoriasis; 80-90% have concurrent skin disease.
5 major forms recognized from classic distal interphalangeal predominant to
spondylitis / sacroiliitis to arthritis mutilans, but overlap of forms common in actuality.
 Nail involvement is usually severe, but no direct relationship between the severity of
skin and joint involvement
 Several HLA types have been associated with psoriatic arthritis, suggesting a genetic
predisposition to the development of joint disease.
Differential Diagnosis
 seborrheic dematitis—most common condition that is confused clinically with
psoriasis
 chronic eczema—may present with thick demarkated plaques
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Intergluteal erythema, discrete rather than diffuse scalp involvment (as in seborrheic
dermatitis), and occurence
Treatment of Psoriasis Vulgaris – A 3 Step Approach
 Step 1: Topical Treatments
 Emollients / moisturizers: petroleum jelly and thick creams, especially effective when
applied after hydrating bath or shower.
 Topical corticosteroids = mainstay for treatment. Moderate to high potency ointments
(e.g., betamethasone 0.5%) +/- occlusion by tape or plastic wrap recommended for
thick plaques on extensor surfaces, whereas low potency (e.g., 0.05% fluocinonide)
usually sufficient for face and intertriginous areas.
 Typical regimen consists of twice daily application. Most patients will show a
decrease in inflammation and plaques.
 new delivery methods: betamethasone in a foam—superior in clinical trials to
betamethasone lotion in scalp psoriasis
 Side Effects: skin atrophy from topical steroid use is not a problem unless
medication is continiously applied after the skin has returned to a normalized
state. Topical steroids generally can be continued as long as the patient has
active lesions.
 Coal tar – usually used in conjunction with steroids, although may be used alone.
Available in a variety of preparations including shampoos, creams, and oils. Tar
preparation in a fatty-acid based lotion (Exorex) may be superior to conventional tar
products, and appears to have similar efficacy to Calcipotrine. Precise mechanism of
action unknown, thought to have anti-proliferative effects.
 Calcipotriene (Dovonex) – vitamin D3 analog that affects growth and differentiation of
keratinocytes. As effective as steroids, although onset not as rapid. May be used in
combination with steroids. Skin irritation is the main adverse event.
 Tazarotene (Tazorac) – topical retinoid (vitamin A derivative), often used in
combination with topical steroids as it reduces skin irritation and augments steroid
effects.
 Topical Calcineurin inhibitors – topical Tacrolimus and Pimecrolimus have been
shown effective in the treatment of psoriasis especially in facial and interginious
areas (allow patients to avoid consequences of chronic steroid use, such as skin
atrophy). However, in 2005, FDA issues an alert about possible risk of skin cancer
and lymphoma in children and adults. No causal link has been established, but these
agents are only used as second line.
 Salicylic acid – keratolytic that softens and removes scale from plaques, allowing
topical meds to penetrate.
 Step 2 – Phototherapy—effect likely through immuno-modulatory properties
 Sunlight – careful sun exposure may improve psoriasis, but sunburn may exacerbate
it.
 UVB (295-320 nm) radiation – erythema inducing doses (3-5x/week until remission)
used for moderate to extensive disease, alone or in combination with topical tar.
 UVB narrow band (311nm) – has been shown to be more effective than the broader
band is some studies, inducing more apoptosis of T-cells
 PUVA – photochemotherapy with oral psoralen (8-methoxypsoralen) followed by
exposure to UVA (320-400 nm) radiation used for moderate-severe disease when
UVB fails. Effective (75% of patients note marked improvement), but increases risk
for premature skin aging and skin cancer.
 High Energy 308 nm excimer laser – treat only involved skin, allows higher doses to
be delivered to the plaques, compared with traditional phototherapy.
 Step 3 – Systemic Therapy
 Methotrexate – effective in severe psoriasis, psoriatic arthritis, and psoriatic nail
disease. Administration can be IV, IM, or SubQ, at doses between 7.5mg and 25mg
per week. Use with folic acid to protect from side effects of MTX, such as stomatitis.
 Acitretin (Soriatane) – vitamin A analog used for treatment of severe psoriasis,
especially pustular and erythrodermic variants. Teratogen, pregnancy
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contraindicated for three years after discontinuing the drug. May be used in
combination with UVB or PUVA.
 Cyclosporine – T-cell suppressor indicated for severe psoriasis not responsive to
other agents. Efficacy of cyclosporine and methotrexate for psoriasis is similar.
Biologics, Immunomodulatory drugs
 Etanercept—recombinant TNF-alpha inhibitor, approved for tx of psoriatic arthritis
and for adults with moderate-severe plaque psoriasis.
 Alefacept – recombinant protein that binds to CD2 receptor on T-lymphocytes,
inhibiting their activation in psoriatic plaques. Approved for treatment of adutls with
moderate-severe chronic plaque psoriasis who are not candidates for systemic
therapy or phototherapy.
 CD4 counts to be checked with each dose
 Do not use therapy if CD 4 < 250/microliter
 Efalizumab – monoclonal ab to CD11a. Approved for moderate-severe plaque
psoriasis. Monitor platelent counts—reports of thrombocytopenia
 Infliximab—TNF-alpha inhibitor, often used in IBD has an “off-label use” in treatment
of psoriasis and is generally well toleated.
General Recommendations
 Mild plaque psoriasis—topical corticosteroids and emollients
 topical retinoids (tazarotene) and calcipotriene as alternatives
 facials/intertriginous areas—topical tacrolimus or pimecrolimus
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Moderate Plaque Psoriasis—combine potent topical steroids and either
calcipotriene, tazarotene, or UVB phototherapy
 calcipotriene + topical steroids—highly effective for short term control
Widespread Psoriasis—phototherapy + systemic therapy (retinoids, methotrexate,
cyclosporine, biologics)
Guttate psoriasis—UVB phototherapy with/without medium potency topical
corticosteroids. treat sourse of strep infection if present
Localized pustular psoriasis (palms and soles)—potent topical steroids and
topical bath PUVA
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