1 Psoriasis Diagnosis & Management Dr Rowan Brown February 2009

2 Pathogenesis Hyperproliferation of keratinoctyes secondary to cytokine stimulus Epidermal thickening (acanthosis) Neutrophil/Lymphocyte infiltration Development of micro-abscesses in the corneum stratum Development of dilated capillaries in the dermis (resulting in bleeding points)

3 Histology hyperkeratosis microabsces s

4 Aetiology Immune mediated: antigen exposed within the corneum stratum associated features HLA CL6 (genetic) Infection: Streptococcus → guttate psoriasis Stress → exacerbations Drugs → Alcohol, β-blockers +nsaids Koebner Phenomenon (occurring in scar tissue)

5 Clinical Features 8 clinical subtypes psoriasis vulgaris (most common) guttate psoriasis (post infective) flexoral psoriasis erythrodermic psoriasis palmoplantar psoriasis psoriatic arthritis nail psoriasis acute pustular psoriasis

6 Acute Pustular Psoriasis Widespread sterile pustules These coalesce to form “lakes of pus” Caused by withdrawl of steroids drugs, pregnancy Septicaemia

7 Psoriasis Vulgaris (Plaque) Common 0.5-3% of population Single or multiple plaques Age (mean age 28yrs) Extensor surfaces, back, sacrum, hairline, knees, elbows

8 Guttate Psoriasis Multiple small lesions post infection Often spontaneously resolve in 2-3/12 Respond poorly to topical agents Differential with pityriasis (scale confined to edge of lesions) pityriasis rosacea - scale confined to edge

9 Flexural Psoriasis Typical eczema distribution Often associated with psoriasis in the hair. Differential with intertrigo

10 Erythrodermic Psoriasis Results when 90% of body affected Precipitated by withdrawl of steroids Consequences: infection dehydration high out-put cardiac failure

11 Palmoplantar Psoriasis Vesicles on soles of hands & feet Painful rather than itchy Chronic condition

12 Psoriatic Arthritis 5 main clinical subtypes: symmetrical polyarthritis asymmetrical oligoarthritis (large joint) spondylitic (sero-negative) distal-interphalangeal (nail) severe mutilans

13 Nail Psoriasis 50% of patients with skin involvement 90% of psoriatic arthritis pitting onycholysis of distal nail bed subungal hyperkeratosis

14 Treatment Predominately benign + chronic condition Topical/Systemic Treatments Topical: - good for single isolated lesions Tar - based preparations Vitamin D-analogues Steroids (rebound) Dithranol (inhibits mitochondrial DNA)

15 Treatment Systemic UVB (nUVB = 311nm wavelength, is more effective) PUVA = Psoralen + UV light Useful for multiple lesions, erythrodermic psoriasis, pustular psoriasis methotrexate (hepatic fibrosis + myelosuppression) cyclosporin (hypertension, hypertrichosis, skin malignancy +lymphoma) retinoids (good for pustular psoriasis)