H. Compton Gift, M.D., M.P.H. and Stephen Holt, M.D., M.S.
1. Be able to differentiate psoriasis from other dermatologic conditions
2. Describe the available treatment modalities for psoriasis
3. Know the indications for referral to a specialist
4. Be able to identify the quality of life issues in the psoriatic patient
A 35-year-old male with a 5-year history of psoriasis comes in complaining that he recently
lost his job as a bartender due to his “repulsive” skin lesions. His father had psoriasis and
was similarly discriminated against as a chef. His physical exam is remarkable for typical
psoriatic plaques involving the scalp and intertriginous sites. Examination of his nails
reveals pitting, with some onycholysis. He comes to you, desperate for treatment.
Note to Preceptors:
It might be helpful to locate the clinic’s copy of Fitzpatrick’s Color Atlas (or a comparable
text) prior to today’s conference, so that you have it available as a visual aid.
1. How can you clinically distinguish psoriasis from other skin
conditions? How is it diagnosed?
In most cases, psoriasis is a clinical diagnosis based on history and
physical exam. The most common patterns include chronic plaque
psoriasis, guttate psoriasis, pustular psoriasis, and erythrodermic
psoriasis, with plaque psoriasis being the most common. Classically, the
lesions are well-demarcated patches with overlying silvery scale on an
erythematous bed. Commonly affected skin regions include the elbows,
knees, lower back and scalp. In some cases, skin flexures including the
submammary, axillary, and intergluteal folds are involved. In addition to
the classic skin findings, psoriasis is often associated with nail bed
findings (e.g. pitting, onycholysis, and subungual hyperkeratosis) and
psoriatic arthritis (5-20% of patients). Psoriasis should be differentiated
from seborrheic dermatosis, discoid lupus, mycosis fungoides (i.e. CTCL),
and tinea infections. Biopsy is seldom necessary to make the diagnosis.
2. What factors may exacerbate his underlying condition?
Several factors are known to worsen psoriasis. Drugs that are the most
common offenders include lithium, beta-blockers, NSAIDS such as
indomethacin, antimalarials, systemic interferon alpha, alcohol, rapid
tapering of systemic steroids, ACE inhibitors, and terbinafine.
Infections, both bacterial and viral, have long been associated with
exacerbation (e.g., post streptococcal flares of guttate psoriasis and
worsening of psoriasis with HIV infection).
Additional aggravating factors include mechanical injury (Koebner
phenomenon), sunburn, and stress. Symptoms also tend to worsen in the
3. Describe the topical therapies that are available. What are the
limitations of these treatments? Which are the most effective?
Numerous topical therapies are available, and primary care physicians
should feel comfortable instituting treatment in patients with mild-
moderate psoriasis. Seventy to eighty percent of patients with psoriasis
can be managed with topical therapy alone, although none of the currently
available treatments are curative.
Possible treatments include emollients, topical steroids, Calcipotriene
(Dovonex), coal tar products, Tazorotene (Tazorac), and Anthralin
(Anthro-Derm). Recent head-to-head trials (of all the aforementioned
therapies except emollients) have failed to demonstrate superiority of any
one class over another (although there may be some added benefit to high
potency topical steroids). Many of them can be used in combination to
limit side effects.
Emollients - offer hydration, keeping the psoriatic skin soft and
minimizing itching. Products containing lactic acid or alpha-hydroxy acid
can be irritating to inflamed or broken skin.
Topical Steroids – The mainstream of topical treatment. Their anti-
inflammatory, antiproliferative, and immunosuppressive properties are
thought to be their primary mechanism of action. The potency of the
steroid prescribed should depend upon the location and thickness of the
lesions, e.g., hydrocortisone 1% cream for face and intertriginous areas,
and the more potent fluocinonide 0.05% for the scalp. Potential side
effects include skin atrophy, telangiectasias, and acne eruption. Usually
high-potency steroids are used initially to control a flare up, followed by
lower potency steroids for maintenance. Penetration of topical steroids
can be enhanced with application of occlusive dressings.
Calcipotriene (Dovonex) –A Vitamin D analogue available in cream,
ointment, or solution that inhibits the growth and differentiation of
keratinocytes. Doses greater than 100 gm/wk may result in hypercalcemia
and skin irritation. Has a slow onset of action.
Coal Tar – A time-honored treatment first described by Goeckeman in
1925. It is thought to have an antiproliferative effect. Products are
available over the counter in the form of shampoos, creams, and oils. It is
most effective when used in combination with topical steroids. Quite
messy and malodorous!
Anthralin - Derived from wood tar, available in oil, ointment, cream, and
solutions. Like coal tar, can lead to staining of clothing, skin, bathtub,
Tazarotene – A topical retinoid which slowly helps to normalize the
proliferation and differentiation of keratinocytes. Effective in the
treatment of mild to moderate plaque psoriasis. Classified as a pregnancy
category X drug, and its use should be avoided in women of childbearing
Of note, adherence to topical therapy regimens is extremely poor (<50%)
due to the significant limitations described above.
4. At what point would it be appropriate to refer him to a specialist?
Referral is recommended when there is uncertainty as to the diagnosis or
failure to respond appropriately to topical therapy after three months.
Extensive, generalized psoriasis, significant disability, or lesions in
delicate locations (e.g. face, genitals) should also precipitate referral.
Generally speaking, if more than 10% of the body surface area is
involved, the patient will likely need systemic therapy, and thus a
5. Discuss other available therapeutic modalities.
As stated above, systemic therapies for generalized psoriasis are best
administered in consultation with a dermatologist.
Established regimens include phototherapy (PUVA) in combination with
systemic agents (e.g., cyclosporine, retinoids, methotrexate, etc.) or
topical agents. PUVA therapy uses oral psoralen to sensitize the patient’s
skin to UVA light, thus intensifying the treatment.
Novel modalities approved by the FDA include “biologic” treatments
(e.g., monoclonal antibodies, cytokines, and fusion proteins) that
specifically target key mechanisms in the pathogenesis of psoriasis.
Examples include Etanercept (Enbrel), Infliximab (Remicaid), Efalizumab
(Raptiva), and others. These agents work by either inhibiting T-cell
activation, leukocyte recruitment, or by directly inhibiting TNF.
6. What other possible issues should be addressed in this patient?
a. Assess for joint pains. All patients with evidence of psoriatic arthritis
should be referred to a rheumatologist.
b. Psychosocial effects. Patients suffer not only from the physical effects
of the skin manifestations themselves, but also from the psychological
impact of having a disfiguring skin disease. Moreover, the treatments
themselves are the source of significant morbidity, from the side effects of
the medications to the extreme inconvenience of their daily application.
Indeed, studies have shown that the psychological impact of psoriasis on
quality of life measures is equal to or greater than the impact from
diabetes, rheumatoid arthritis, or cancer. Informing patients and their
families that psoriasis is not contagious may lessen the stigma of the
disease; physically touching the skin lesions can be particularly beneficial
and communicates to the patient that they are not contagious.
Treating the psychosocial aspects of the disease requires recognition of
both the attitude of the general population, which may result in not so
subtle discrimination, and the patient’s perspective. Patients should be
referred to the National Psoriasis Foundation website for additional
psychosocial support, educational materials, etc.
7. Bonus Question: What is the currently accepted theory regarding the
pathophysiology of psoriasis?
Dysregulation of T-cells and upregulation of TNF-, leading to
recruitment of other pro-inflammatory immune cells, hyperproliferation of
epidermal keratinocytes, and hyperkeratosis.
1. Smith CH, Barker JN. Psoriasis and its management. British Medical Journal. 2006.
2. Jobling R. Psoriasis. British Medical Journal. 2007. 334:953-954.
3. Schon MP, Boehncke WH. Psoriasis. New England Journal of Medicine. 2005.
1. Cayce KA, et al. A red, scaly rash: How to recognize and treat psoriasis. JCOM.
2. National Psoriasis Foundation website: www.psoriasis.org
3. Hunter J, Savin J, and Dahl M. Clinical Dermatology. 3rd ed. Malden, MA:
Blackwell Science Ltd; 2002.