What is psoriasis?
Autoimmune chronic inflammatory diseases of the skin. |
Occurs due to overstimulation of immune cells that causes excessive proliferation of keratinocytes. |
Silvery scaling of skin and itching. |
Not contagious and not severe in many cases (outpatient mx) |
General features
Erythematous papules and silvery-white scaling plaques |
Well demarcated, raised, red patches |
Usually not itchy (pruritus is typically mild - 80% of cases) |
Affects scalp, back, elbows and knees (extensor surfaces), and nails (thimble pitting). |
Erythematous- superficial redness caused by dilation of capillaries.
Nail pitting - small, round depression in the nail.
Clinical variants.
Plaque psoriasis |
Well demarcated individual thick, scaly, erythematous lesions |
Guttate psoriasis |
numerous small, scaly, red or pink, tear-drop shaped lesions |
Psoriatic nail disease |
Drug-induces psoriasis |
Psoriatic arthritis |
Inflammation of joints on hand, feet and spine that can occur with psoriasis |
Pustular psoriasis |
appears as red bumps filled with noninfectious pus (pustules) |
Flexural/inverse psoriasis |
occurs in skin folds and flexor surfaces creases of joints |
Erythodermic psoriasis |
generalized erythematous lesions. |
Scalp psoriasis |
affects the scalp |
Plaque Psoriasis
Most common type |
Thick, scaly, erythematous lesions |
Lesions are red with silver-white scaling |
Common sites: |
Extensor surfaces of elbows and knees. |
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Lower back |
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Scalp (can cause temporary hair loss) |
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Palms |
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Nails- pitting and onycholysis |
Onycholysis - separation of the nail from the nail bed
Guttate Psoriasis
Often preceded by Streptococcal infection (Streptococcus pharyngitis) |
Resolves quickly |
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Erythrodermic Psoriasis
There is increase in cutaneous blood flow, heat loss, and water loss |
Skin becomes red. |
Scaling is absent (although this can proceed the erythroderma). |
Inverse/Flexural Psoriasis
Common sites: |
Genitals (between thigh and groin) |
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Armpits |
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Under an overweight abdomen (panniculus) |
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Under the breasts (inflammatory fold) |
Increased by friction and sweat |
Vulnerable to fungal infections |
Looks like smooth inflamed patches on skin |
Psoriatic arthritis
Joint and Connective tissue inflammation. |
Most common joints affected: |
Fingers and toes |
Results in Dacylitis |
Other joints: |
Knees, hips, spine (spondylitis) |
Morning stiffness of affected joints |
Dacylitis - Sausage shaped swelling of fingers and toes.
Pustular psoriasis
Can be localized, common to hands and feet |
Palmoplantar pustulosis |
Or generalized, widespread patches |
Etiology
Genetics |
Precipitating factors |
1. Infections |
Pharyngitis, HIV |
2. Drugs |
Beta blockers, anti-malarial, lithium, NSAIDs, systemic steroid withdrawal |
3. Alcohol and smoking |
4. Emotional stress |
5. Local trauma |
Grading
Mild (3% of the body) |
Moderate (3-10% of the body) |
Severe |
Degree of severity is based on: |
proportion of body surface area affected |
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disease activity (plaque, redness, scaling) |
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response to previous treatments |
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impact of the disease in the patient |
Diagnosis
Based on appearance of the skin |
Skin biopsy, or scrapping - to rule out other disorders |
Biopsy shows clubbed rete pegs if positive for psoriasis |
Auspitz sign |
small pinpoint bleeding when scales are scraped off |
Treatment
Mild disease |
Emolients |
Mild-to-moderate disease |
Topical corticosteroids (triamcinolone, fluocinonide, clobetasol), emollients, topical retinoids (tazarotene), vitamin D analogs (calcipotriene, calcitriol) |
For facial areas |
Topical tacrolimus and Pimecrolimus |
Severe |
Phototherapy, MTX, cyclosporine, anti-T cell agent, anti-TNF agent |
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Vitamin D analogs
Avoid use on delicate skin areas (face, flexures) because of irritation. |
Combine with steroids to increase efficiency |
Coal Tar
Anti-inflammatory, anti-pruritic, anti-mitotic |
Systemic Therapies
For severe generalized psoriasis intolerant after topical therapy |
MTX |
S/E: hepatic fibrosis, myelosuppression, teratogenic |
Hydroxyurea |
S/E: myelosuppression, skin reactions, liver toxicity, teratogenic |
Cyclosporine |
S/E: renal toxicity, HTN, gingival hypertrophy |
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