Psoriasis and Other Papulosquamous Disease

• Definitions– Psoriasis is the most common

chronic papulosquamous disease

– The classic lesion of psoriasis is a well-demarcated erythematous plaque with a silvery (micaceous) scale

– Removal of the scale commonly results in bleeding (Auspitz sign)

• Psoriasis is common (2% of the population)• As a chronic inflammatory disease it is associated

with systemic disease that might be preventable• Cardiovascular disease• Obesity and smoking precede the development

of moderate to severe psoriasis• Early, aggressive treatment might lessen the

occurrence of some of the co-morbidities and improve survival

Epidemiology

• Psoriasis affects roughly 2% of the population• Equal sex distribution.• Onset is bimodal – Peaks between 20-30 and

50-60 years of age, but it can occur at any age from birth to death.

• Familial cases are not uncommon

Etiology/Pathogenesis

• Genetic basis for the disease is not fully understood• Environmental trigger factors• Trauma – Koebner phenomenon• Stress• Streptococcal infection• Drugs – e.g. lithium, beta blockers, possibly antimalarial

agents• Pustular psoriasis has been associated with the withdrawal of

corticosteroid therapy• Psoriasis is a disease associated with chronic inflammation

and a variety of immunologic and cytokine abnormalities are believed to be related to disease expression

Clinical Variants

• Psoriasis vulgaris• Guttate psoriasis• Pustular psoriasis• Inverse psoriasis• Erythrodermic psoriasis

Psoriatic arthritis

• Affects between 7 & 21% of patients with psoriasis

• May occur prior to, concurrent with or subsequent to psoriasis

• More common in patients with moderate to severe cutaneous disease and those with nail involvement

Psoriasis Vulgaris

Guttate Psoriasis

Pustular Psoriasis

Localized pustular psoriasis

Generalized pustular psoriasis

Erythrodermic Psoriasis

Koebner Phenomenon

Nail Disease in Psoriasis

Psoriatic Arthritis

Diagnosis of Psoriasis

• Clinical diagnosis• Exclude other papulosquamous diseases and

chronic eczemas• When the clinical disease is typical, then the

histopathological features are also characteristic, however when the disease is atypical the histopathology is often non-specific

Differential Diagnosis

• Chronic Dermatitis• Seborrheic Dermatitis• Pityriasis rosea• Lupus erythematosus• Dermatophyte infection• Cutaneous T-cell lymphoma (mycosis fungoides)• Lichen planus

Chronic Atopic Dermatitis

Chronic Dermatitis

Pityriasis Rosea

Secondary Syphilis

Cutaneous Lupus Erythematosus

Dermatomyositis

Dermatophyte Infection

Onychomycosis

Cutaneous T-cell Lymphoma