AUTHOR INFORMATION

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Authored by Randy Park, MD, Chair, Associate Professor, Department of Emergency Medicine, Denton Regional Medical Center

Edited by Dana A Stearns, MD, Assistant Director of Undergraduate Education, Department of Emergency Medicine, Massachusetts General Hospital; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Mark W Fourre, MD, Program Director, Department of Emergency Medicine, Maine Medical Center, Associate Clinical Professor, Department of Surgery, University of Vermont School of Medicine; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; and Robert E O'Connor, MD, MPH, Director of Education and Research, Department of Emergency Medicine, Christiana Care Health System; Professor of Emergency Medicine, Thomas Jefferson University

Author's Email:	Randy Park, MD
Editor's Email:	Dana A Stearns, MD

eMedicine Journal, June 22 2006, VOLUME 7, Number 6

INTRODUCTION

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Background: Psoriasis is a noncontagious skin disorder that most commonly appears as inflamed, edematous skin lesions covered with a silvery white scale. The most common type of psoriasis is plaque psoriasis.

Flares may be related to systemic or environmental factors, including life stress events and infections.

Discoid/plaque psoriasis is the most common type and is characterized by patches on the scalp, trunk, and limbs. The nails may be pitted and/or thickened.

Psoriasis may occur on the oral mucosa as well, although it is rare.

Pathophysiology: The skin is the primary organ affected, but joints also are affected in 10% of cases.

Frequency:

• In the US: Between 2 and 2.6% of the US population is affected. Between 150,000 and 260,000 new cases of psoriasis occur annually.

• Internationally: Incidence of psoriasis is dependent on the climate and genetic heritage of the population. It is less common in the tropics and in dark-skinned persons.

Mortality/Morbidity:

• Four hundred people die annually from psoriasis-related causes in the US.

• Approximately 1.5 million people with psoriatic arthritis seek medical care each year in the US.

Race: Psoriasis is more common in whites.

Sex: Psoriasis is slightly more common in women.

Age: Approximately 10-15% of new cases begin in children younger than 10 years. The median age at onset is 28 years.

CLINICAL

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History:

• Worsening of a long-term erythematous scaly area

• Sudden onset of many small areas of scaly redness

• Recent streptococcal throat infection, viral infection, immunization, use of antimalarial drug, or trauma

• Family history of similar rash

• Pain

• Pruritus

• No fever

• Vesicles

• Long-term rash with recent presentation of joint pain

Physical: Findings on physical examination depend on the type of psoriasis.

• Plaque psoriasis is characterized by raised inflamed lesions covered with a silvery white scale. The scale may be scraped away to reveal inflamed skin beneath. This is most common on the extensor surfaces of the knees, elbows, scalp, and trunk.

• Guttate psoriasis presents as small red dots of psoriasis that usually appear on the trunk, arms, and legs; the lesions may have some scale. It frequently appears suddenly after an upper respiratory infection (URI).

• Inverse psoriasis occurs on the flexural surfaces, armpit, groin, under the breast, and in the skin folds and is characterized by smooth, inflamed lesions without scaling.

• Pustular psoriasis presents as sterile pustules appearing on the hands and feet or, at times, diffusely, and may cycle through erythema, pustules, and scaling.

• Erythrodermic psoriasis presents as generalized erythema, pain, itching, and fine scaling.

• Scalp psoriasis affects approximately 50% of patients, presenting as erythematous raised plaques with silvery white scales on the scalp.

• Nail psoriasis may cause pits on the nails, which may develop yellowish color and become thickened. Nails may separate from the nail bed.

• Psoriatic arthritis affects approximately 10% of those with skin symptoms. The arthritis is usually in the hands, feet, and, at times, in larger joints. It produces stiffness, pain, and progressive joint damage.

• Oral psoriasis may present with whitish lesions on the oral mucosa, which may appear to change in severity from day to day. It may also present as severe cheilosis with extension onto the surrounding skin, crossing the vermillion border.

Causes:

• Lesions of psoriasis are caused by an increase in the turnover rate of dermal cells from the normal 23 days to 3-5 days in affected areas.

• Silver scale on the surface of lesions is a layer of dead skin cells and may be scraped away from most lesions even if the scale is not apparent on visual inspection.

• Patients with psoriasis have a genetic predisposition for the disease.

• Gene locus has been determined.

• The trigger event may be unknown in most cases but is likely an immunologic event.

• Commonly, the first lesion appears after an upper respiratory infection, such as streptococcal pharyngitis.

• Perceived stress can cause exacerbation of psoriasis. Some authors suggest that psoriasis is a stress-related disease and offer findings of increased concentrations of neurotransmitters in psoriatic plaques.

• Autoimmune function

• Significant evidence is accumulating that psoriasis is an autoimmune disease.

• Lesions of psoriasis are associated with increased activity of T cells in underlying skin.

• Guttate psoriasis has been recognized to appear following certain immunologically active events, such as streptococcal pharyngitis, cessation of steroid therapy, and use of antimalaria drugs.

• Superantigens and T cells

• Psoriasis is related to excess T-cell activity. Experimental models can be induced by stimulation with streptococcal superantigen, which cross-reacts with dermal collagen. This small peptide has been shown to cause increased activity among T cells in patients with psoriasis but not in control groups.

• Some of the newer drugs used to treat severe psoriasis directly modify the function of lymphocytes.

• Also of significance is that 2.5% of those with HIV develop psoriasis during the course of the disease.

DIFFERENTIALS

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Dermatitis, Atopic
Dermatitis, Contact
Gout and Pseudogout
Pityriasis Alba
Pityriasis Rosea
[Reiter Syndrome]

Syphilis
Tinea

Other Problems to be Considered:

Seborrheic dermatitis
Diaper dermatitis
Onychomycosis
Squamous cell carcinoma
Nummular eczema
Lichen planus
Lichen simplex chronicus
Mycosis fungoides
Subcorneal pustulosis
Pustular eruptions

WORKUP

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Lab Studies:

• Test for rheumatoid factor (RF) is negative.

• Erythrocyte sedimentation rate (ESR) is usually normal.

• Uric acid level may be elevated in psoriasis, causing confusion with gout in psoriatic arthritis.

• Fluid from vesicles or pustules is sterile with lymphocytic infiltrate.

• Perform latex fixation test.

• Perform fungal studies.

Imaging Studies:

• Radiographs of affected joints can be helpful in differentiating types of arthritis.

• Bone scans can identify joint involvement early.

Procedures:

• Although most cases of psoriasis are diagnosed clinically, some, particularly the pustular forms, can be difficult to recognize. In these cases, dermatologic biopsy can be used to make diagnosis.

TREATMENT

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Emergency Department Care:

• Patients with guttate, erythrodermic, or pustular psoriasis may present to the emergency department.

• In each of these cases, restoration of the barrier function of the skin is of prime concern. This can be performed with cleaning and bandaging.

• Plaque and scalp lesions are frequently encountered in patients seeking care for other problems, and initial treatment of the lesions should be offered.

• Solar or ultraviolet radiation may be helpful.

• Oatmeal baths may be helpful.

Consultations: This disease is a chronic problem, and consultation for follow-up with a dermatologist or rheumatologist is appropriate.

• Psoriatic lesions on the palms are especially debilitating and require consultation.

• Patients with infectious diseases and psoriasis may be using drugs that modify immunologic response and render them immunocompromised. Investigation into the type of therapy is important and if such an agent is identified, referral and close follow-up is needed.

MEDICATION

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Many drugs that affect the rate of production of skin cells are used in psoriasis therapy alone or in combination with light therapy, stress reduction, and climatotherapy. Adjuncts to treatment include sunshine, moisturizers, and salicylic acid as a scale-removing agent. Generally, these therapies are used for patients with less than 20% of body surface area involved, unless the lesions are physically, socially, or economically disabling.

Treatments for more general or advanced psoriasis include UV-A light, psoralen plus UV-A light (PUVA), retinoids (eg, isotretinoin [Accutane], acitretin [Soriatane]), methotrexate (particularly for arthritis), cyclosporine (Neoral, Sandimmune), etanercept (Enbrel), and alefacept (Amevive).

The drugs listed below are used for initial treatment.

Drug Category: Topical corticosteroids -- These agents are used to reduce plaque formation. These agents have anti-inflammatory effects and may cause profound and varied metabolic activities. In addition, these agents modify the body's immune response to diverse stimuli.

Drug Name	Triamcinolone acetonide (Aristocort, Kenalog) 0.1% cream -- Treats inflammatory dermatosis responsive to steroids. Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing capillary permeability. Has mild potency and is the first DOC for most patients.
Adult Dose	Apply a thin film bid/tid to lesions daily after bathing, since moist skin absorbs the drug better; continue until a satisfactory response is obtained
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; fungal infections
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Do not use in patients diagnosed with decreased skin circulation; may cause thinning of skin, striae, increased ocular pressure, and tachyphylaxis

Drug Name	Betamethasone dipropionate (Diprolene, Diprosone), 0.05% cream -- Treats inflammatory dermatosis responsive to steroids. Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing capillary permeability. Is a potent topical steroid and is DOC if psoriasis is resistant to milder forms.
Adult Dose	Apply a thin film bid/qid until a favorable response is obtained
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; treatment of rosacea; paronychia; cellulitis; impetigo; angular cheilitis; erythrasma; erysipelas; perioral dermatitis; acne
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Do not use in patients diagnosed with decreased skin circulation; can cause atrophic changes in certain areas of body, such as the groin, face, and axillae; if an infection develops, treat with an antifungal or antibacterial agent; if there is no satisfactory response, discontinue the corticosteroid until infection has been controlled; do not use topical corticosteroids as a monotherapy in the treatment of widespread plaque psoriasis

Drug Category: Coal tar -- An inexpensive treatment that is available over the counter in shampoos or lotions for use in widespread areas of involvement. It is particularly useful in hair-bearing areas. Some recent research has shown the 1% concentration may be superior in control of lesions to more concentrated preparations.

Drug Name	Coal tar 1-10% (DHS Tar, Doctar, Theraplex T) -- Antipruritic and antibacterial that inhibits deregulated epidermal proliferation and dermal infiltration. Does not injure the normal skin when applied widely and enhances the usefulness of phototherapy. Generally is used as a second-line drug therapy due to messy application, except for shampoos, which may be used and rinsed at once.
Adult Dose	Rub a copious amount of shampoo into the wet hair and scalp or skin and rinse thoroughly; repeat the treatment, leave on for 5 min, and rinse thoroughly Frequency varies depending on the manufacturer's instructions; may use from qd to twice a week; for severe psoriasis, use daily
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; acute inflammation or open lesions
Interactions	None reported
Pregnancy	A - Safe in pregnancy
Precautions	Do not apply to eyes; if irritation develops or response is unsatisfactory, discontinue use

Drug Category: Keratolytic agents -- Used to remove scale, to smooth the skin, and to treat hyperkeratosis.

Drug Name	Anthralin 0.1-1% (Drithocreme, Anthra-Derm) -- Reduces the rate of cell proliferation. Its chemically reducing properties may also upset the oxidative metabolic processes, further reducing epidermal mitosis. It is not the first or second DOC due to irritation problems of normal skin surrounding lesions and staining of the skin.
Adult Dose	Use sparingly and apply gently and carefully to psoriatic lesions only daily; to avoid unnecessary staining of clothing, do not apply excessive amounts
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; acutely or actively swollen psoriatic lesions
Interactions	Allow an interval of at least 1 week between the discontinuation of corticosteroids and the initiation of anthralin therapy; this reduces complications resulting from the rebound phenomenon caused by long-term use of corticosteroids and withdrawal of corticosteroid treatment
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in patients with renal disease; do not apply the treatment to the face or genitalia, and avoid eye contact; if redness develops, discontinue application

Drug Category: Vitamin D-3 analogs -- Used in patients with lesions resistant to older therapy or with lesions on the face or exposed areas where thinning of the skin would pose cosmetic problems.

Drug Name	Calcipotriene (Dovonex) -- A synthetic vitamin D-3 analog that regulates skin cell production and development. It is used in the treatment of moderate plaque psoriasis. This new treatment does not cause long-term skin thinning or systemic effects. It is more expensive than steroids.
Adult Dose	Apply a thin film bid to the affected skin only until a favorable response
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; hypercalcemia; vitamin D toxicity
Interactions	None reported with the topical use
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	The lesions and surrounding uninvolved skin may be irritated following treatment; if this happens, discontinue treatment; it may transiently but reversibly elevate serum calcium; discontinue if increase is outside the normal range

Drug Name	Calcipotriene and betamethasone topical ointment (Taclonex) -- Calcipotriene is a synthetic vitamin D-3 analog that regulates skin cell production and development. Inhibits epidermal proliferation, promotes keratinocyte differentiation, and has immunosuppressive effects on lymphoid cells. Betamethasone is a corticosteroid that decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing capillary permeability. Available as a topical ointment containing calcipotriene 0.005% and betamethasone dipropionate 0.064%. Indicated for psoriasis vulgaris.
Adult Dose	Apply to affected area qd; not to exceed 100 g/wk; do not use > 4 wk
Pediatric Dose	<18 years: Not established >18 years: Apply as in adults
Contraindications	Documented hypersensitivity; known or suspected calcium metabolism disorders; erythrodermic, exfoliative, or pustular psoriasis
Interactions	Coadministration with other corticosteroids may increase toxicity
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	May cause hypercalcemia; systemic absorption of topical corticosteroids has caused HPA-axis suppression, Cushing syndrome manifestations, hyperglycemia, and glucosuria; not for prolonged use (ie, > 4 wk), large surface areas (ie, >30% of body surface area), or application with occlusive dressings; do not use on face, eyes, axillae, or groin; may cause contact dermatitis

Drug Category: Topical retinoids -- Aqueous gel formulations are odorless and colorless, and no long-term skin damage has been noted with topical retinoids. There is also no threat of worsening if the therapy is withdrawn, as with steroids. These drugs should not be used in women if pregnancy is a possibility.

Drug Name	Tazarotene (Tazorac) aqueous gel 0.05% and 0.1% -- A retinoid prodrug that is converted to its active form in the body and modulates differentiation and proliferation of epithelial tissue and perhaps has anti-inflammatory and immunomodulatory activities. May be the DOC for those with facial lesions who are not at risk of pregnancy.
Adult Dose	Apply a thin film qd only to cover no more than 20% of body surface area; use enough (2 mg/cm2) to cover the lesion(s)
Pediatric Dose	<12 years: Not established >12 years: Administer as in adults
Contraindications	Documented hypersensitivity
Interactions	None reported
Pregnancy	X - Contraindicated in pregnancy
Precautions	May cause a feeling of burning or stinging; discontinue treatment if irritation is excessive; avoid contact with eyes, eyelids, and mouth; rinse thoroughly with water if contact with eyes occurs; retinoids on eczematous skin may cause severe irritation and should not be used; caution patients to take protective measures against exposure to ultraviolet or sunlight, since photosensitivity may result

FOLLOW-UP

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Deterrence/Prevention:

• Avoid injury to skin, including sunburn and other physical trauma, as these areas may develop psoriasis. This problem is known as the Koebner phenomenon.

• Avoid drugs known to worsen the problem (eg, chloroquine, beta-blockers, aspirin).

Complications:

• Secondary infections

• Psoriatic arthritis

• Mitral valve prolapse

Prognosis:

• Lifelong involvement, with waxing and waning, with progression to arthritis in about 10% of cases

• Usually benign

• May be refractory to treatment

Patient Education:

• Most psoriasis can be controlled at a tolerable level with the regular application of care measures.

• For excellent patient education resources, visit eMedicine's Psoriasis Center. Also, see eMedicine's patient education articles Psoriasis, What Is Psoriasis?, Types of Psoriasis, Nail Psoriasis, and Understanding Psoriasis Medications.

MISCELLANEOUS

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Medical/Legal Pitfalls:

• Abruptly stopping steroid therapy in psoriasis or adding known irritant drugs can result in the sudden worsening of psoriasis or appearance of a new form. Commonly, this new form is guttate psoriasis, which is much more severe and cosmetically problematic than the preexisting plaque type.

• Many of the therapies for psoriasis manipulate the function of the immune system and expose the patient to risk of severe infections while blunting the body's response. In these patients, findings suggestive of minor infections must be taken seriously, and the risk versus the benefit of continuing the drug in the face of the infection must be weighed.

TEST QUESTIONS

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CME Question 1: A patient has experienced a chronic red, scaly lesion on the left knee since age 20 years. Two weeks ago she was treated for strep throat with penicillin and seemed to recover uneventfully. Three days ago she broke out in a rash over the upper chest. Now the rash involves the entire torso and the proximal extremities. The lesions are 2-4 mm in diameter, were initially red and raised, and then became scaly with silver scale and pruritic. What is the most likely diagnosis?

A: Pityriasis
B: Impetigo
C: Guttate psoriasis
D: Mononucleosis
E: Gonorrhea

The correct answer is C: Plaque psoriasis is commonly aggravated by a streptococcal infection and develops into the guttate form.

CME Question 2: A fertile 20-year-old woman was treated with topical steroids for psoriasis on the face. The lesion resolved, but she was left with cosmetically problematic thinning of the skin in the region of the lesions. She has now developed a new lesion on the cheek. What treatment can safely be offered?

A: Topical steroids
B: Systemic steroids
C: Tazarotene (Tazorac)
D: Calcipotriene (Dovonex)
E: Methotrexate

The correct answer is D: Calcipotriene is the correct treatment. Tazarotene and methotrexate are contraindicated in pregnancy. Topical steroids will cause further cosmetic problems. Systemic steroids should be avoided in patients with psoriasis.

Pearl Question 1 (T/F): A patient with psoriasis presents with a small laceration, which is repaired in the ED. Later, psoriasis develops in the line of the wound and at each of the suture entry and exit points. This happened because the wound was infected.

The correct answer is False: Not necessarily. This is an example of the Koebner phenomenon. Patients with psoriasis frequently develop new lesions at the site of wounds. This is likely a result of the activated state of the T cells in the patient.

Pearl Question 2 (T/F): The median age of onset of psoriasis is 28 years.

The correct answer is True: The median age is 28 years, but psoriasis may occur at any age, even infancy.

Pearl Question 3 (T/F): When choosing malaria prophylaxis in a patient with psoriasis, between doxycycline and chloroquine, doxycycline would be the better choice.

The correct answer is True: Chloroquine has been shown to stimulate the development of guttate psoriasis and doxycycline has not. Therefore, the best choice is doxycycline.

Pearl Question 4 (T/F): In choosing an antihypertensive for a patient with moderately severe psoriasis, an ACE inhibitor is the better choice over a beta-blocker.

The correct answer is True: The other things being equal, the beta-blocker is more likely to cause problems with the management of psoriasis.

PICTURES

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Caption: Picture 1. Guttate psoriasis erupted in this patient after topical steroid therapy was withdrawn during a pregnancy. Contributed by Randy Park, MD
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Caption: Picture 2. Plaque psoriasis is most common on the extensor surfaces of the knees and elbows. Contributed by Randy Park, MD
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Caption: Picture 3. Plaque psoriasis is raised, roughened, and covered with white or silver scale with underlying erythema. Contributed by Randy Park, MD
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BIBLIOGRAPHY

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• Bowcock AM: Genetic locus for psoriasis identified. Ann Med 1995 Apr; 27(2): 183-6[Medline].
• Bowcock AM, Barker JN: Genetics of psoriasis: the potential impact on new therapies. J Am Acad Dermatol 2003 Aug; 49(2 Suppl): S51-6[Medline].
• Bruce AJ, Rogers RS: Oral psoriasis. Dermatol Clin 2003 Jan; 21(1): 99-104[Medline].
• Cuellar ML, Espinoza LR: Psoriatic arthritis. Current developments. J Fla Med Assoc 1995 May; 82(5): 338-42[Medline].
• Elder JT, Henseler T, Christophers E, et al: Of genes and antigens: the inheritance of psoriasis. J Invest Dermatol 1994 Nov; 103(5 Suppl): 150S-153S[Medline].
• Farber EM, Nall L: Psoriasis. A review of recent advances in treatment. Drugs 1984 Oct; 28(4): 324-46[Medline].
• Farber EM: Therapeutic perspectives in psoriasis. Int J Dermatol 1995 Jul; 34(7): 456-60[Medline].
• Greaves MW, Weinstein GD: Treatment of psoriasis. N Engl J Med 1995 Mar 2; 332(9): 581-8[Medline].
• Lebwohl M: Combining the new biologic agents with our current psoriasis armamentarium. J Am Acad Dermatol 2003 Aug; 49(2 Suppl): S118-24[Medline].
• Lebwohl MG: The evolution of vitamin D analogues for the treatment of psoriasis. Arch Dermatol 1995 Nov; 131(11): 1323-4[Medline].
• Lewis HM: Therapeutic progress. II: Treatment of psoriasis. J Clin Pharm Ther 1994 Aug; 19(4): 223-32[Medline].
• Menter MA, Krueger GC, Feldman SR, Weinstein GD: Psoriasis treatment 2003 at the new millennium: position paper on behalf of the authors. J Am Acad Dermatol 2003 Aug; 49(2 Suppl): S39-43[Medline].
• Naldi L: Psoriasis. Dermatol Clin 1995 Jul; 13(3): 635-47[Medline].
• Pines A, Ehrenfeld M, Fisman EZ, et al: Mitral valve prolapse in psoriatic arthritis. Arch Intern Med 1986 Jul; 146(7): 1371-3[Medline].
• Raychaudhuri SP, Rein G, Farber EM: Neuropathogenesis and neuropharmacology of psoriasis. Int J Dermatol 1995 Oct; 34(10): 685-93[Medline].
• Task Force on Psoriasis: Guidelines of care for psoriasis. Committee on Guidelines of Care. Task Force on Psoriasis. J Am Acad Dermatol 1993 Apr; 28(4): 632-7[Medline].
• Valdimarsson H, Sigmundsdottir H, Jonsdottir I: Is psoriasis induced by streptococcal superantigens and maintained by M- protein-specific T cells that cross-react with keratin? Clin Exp Immunol 1997 Jan; 107 Suppl 1: 21-4[Medline].
• Weinstein GD: Tazarotene: A novel retinoid for the topical treatment of psoriasis. Pharmacy and Therapeutics 1997 Aug; 377-81.

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Author Information | Introduction | Clinical | Differentials | Workup | Treatment | Medication | Follow-up | Miscellaneous | Test Questions | Pictures | Bibliography