Download Psoriasis

PSORIASIS
Daniel Federman, M.D.
WEEK 6: 02/07 – 02/11/05
Learning Objectives:
1. To understand how to treat psoriasis with topical therapy
2. To be able to understand extracutaneous manifestations of psoriasis
3. To be familiar with systemic therapies for psoriasis as well as their
toxicities
CASE ONE:
A 33-year-old man comes in for an urgent visit complaining of skin lesions for
several months. He says that he has a brother with psoriasis and is afraid that he
may have the condition, too. On exam, you see several well-demarcated,
erythematous, pink plaques with superficial scale over his elbows and knees.
Examination of his nails reveals pitting and onycholysis.
Questions:
1. Do you think he has psoriasis?
Yes, he is suffering from the most common form of psoriasis, plaque-type
psoriasis, which has a predilection for knees, elbows, scalp, and the gluteal cleft.
While this is the most common form of psoriasis, other forms include the guttate
variant (which often occurs in the setting of a streptococcal infection), inverse
psoriasis (which does not have scale and occurs in intertriginous areas), pustular
psoriasis, and erythrodermic psoriasis. The latter two forms though rare, are
associated with higher morbidity. He has a family history of psoriasis. A genetic
predisposition combined with environmental processes (infection, winter weather,
stress, certain medications, etc.) are potential triggering factors.
2. Can there be involvement outside of the skin?
In addition to nail involvement, 10-30% of patients with psoriasis develop
arthritis, which most commonly, but not invariably, develops after the skin
disease. The most common forms of psoriatic arthritis are an asymmetrical
oligoarticular arthritis of the distal interphalangeal joints and a seronegative
spondyloarthritis. Sausage digits may also occur. We cannot forget the
psychological impact of psoriasis. Patients may suffer a lack of self-esteem, may
be less willing to engage in a physical relationship, and suffer an impaired quality
of life.
3. What therapy should you initiate?
First-line therapies for localized, mild disease include topical corticosteroids and
topical vitamin D analogues. While generic topical corticosteroids are generally
less expensive than vitamin D analogues, chronic topical corticosteroid use may
lead to local side effects (atrophy and telangiectasia). For disease on the face,
genitals, and intertriginous areas, a low potency topical corticosteroid, such as
hydrocortisone, can be used. For the trunk and extremities, a mid-potency topical
corticosteroid, such as triamcinolone, can be used. Topical vitamin D analogues
are not associated with atrophy and telangiectasia, but are slower acting and
more expensive. Several experts use strategies combining these 2 agents in order
to decrease potential side effects, such as using a topical corticosteroid in the
evening and a vitamin D analogue in the morning. Others prescribe a topical
vitamin D analogue twice daily during the week and twice daily topical
corticosteroids on the weekends. Other topical therapies include tar, anthralin,
and the topical retinoid, tazarotene. Tar is malodorous and staining, anthralin is
not only staining, but irritates normal skin, and tazarotene, which is relatively
expensive, is irritating and slightly less effective.
4. Should he worsen or be unwilling to apply topical therapy, what systemic
options are available?
While topical therapy is appropriate for this patient, we must remember that
many patients are unable or unwilling to apply topical therapy twice daily.
Should he worsen, other therapeutic options that are available to dermatologists
include phototherapy, or systemic therapy with acitretin, methotrexate,
cyclosporine, or newer biologic agents. Primary care physicians should be able
to treat mild psoriasis with topical agents and be familiar with potential side
effects of these other systemic agents (see text).
References:
1. Cayce, K.A. et al. A red, scaly rash: how to recognize and treat psoriasis. JCOM.
July 2004; 11: 463-474.