Psoriasis and Psoriatic Arthritis

Psoriasis and Psoriatic Arthritis

Psoriasis is a chonic skin disorder characterised by excessive proliferation of keratinocytes resulting in formation of thickened scaly plaques, itching and inflammatory changes in epidermis and dermis.

Types: guttate, pustular, arthritis

2. There is a strong genetic component in the pathogenesis of psoriasis. Certain ethnicity such as Indians; HLA/MHC; Familial clustering; are associated with psoriasis.

Patients with celiac disease also have higher prevalence of psoriasis.

3. Psoriatic lesion is erythematous papule topped by loosely adherent scale.

Chronic plaques are symmetric, sharply demarcated, erythematous and silvery scale affecting the intergluteal folds, elbow, scalp, fingernails, toenails and knees.

Koebner's Phemomenon is the development of psoriatic lesion at traumatic sites (sunburn, scratch)

Auspitz sign may be demonstrated by scraping the scale which results in bleeding points.

Nail involvement is common - pitting nail plate, hyperkeratosis, onychodystrophy and onycholysis.

Patients often complain of variable pruritus, soreness and bleeding.

** The biggest impact of psoriasis is the psychosocial functioning of patients!

4. Guttate form occurs after streptococcal pharyngitis - multiple droplike lesions on the extremities and trunk.

5. Arthritic form is classified as seronegative spondyloarthritis and manifests as arthritis, dactylitis, spondylitis and enthesitis.

Arthritis is inflammatory in nature - symptoms of prolonged morning stiffness, joint erythema, warmth, swelling and joint effusion

Distribution of joint involvement: DIPJ type, symmetric type, asymmetric oligoarthritis, axial type and arthritis mutilans.

Dactylitis - diffuse swelling of digit
Enthesitis - inflammation at site of insertion of tendon into bone. Usually occurs at Archilles tendon-calcaneus. Manifests as swelling and tenderness.

Spondyloarthritis - sacroilitis, axial spine inflammation

Other manifestation - conjunctivitis and uveitis

6. Psoriasis is diagnosed clinically. Blood result and skin biopsy are rarely needed for confirnation.

Psoriatic Arthritis is diagnosed using Classification Criteria for Psoriatic Arthritis (CASPAR) - Score of 3 or higher is diagnostic

Thus laboratory workouts are tailored according to CASPAR. Acute phase reactants (ESR, CRP) is often raised. FBC may show anaemia of chronic illness. RF and ACPA is negative in 90% of the cases.

Radiological investigations of involved joints may show soft tissue swelling, joint space narrowing, subluxation, erosive changes. New bone formation such as periostitis and fusion may also occur. Digital erosive changes with adjacent heterotopic bone formation may result in "pencil in cup" deformity.

Other workouts if available include: identification of HLA B27, arthrocentesis to rule out crystal deposition disease and inflammatory synovial fluid.

7. Treatment of Psoriasis can be divided into non-pharmacological and pharmacological therapy:

Non-pharmacological therapy:
sunbathing
eliminating triggering factors
warm water bath and skin moisturisers
local hyperthermia
surgical taping or dressing

Pharmacological therapy:
topical steroids +/- aspirin cream
calcipotriene
tar product
anthralin
retinoids
oral PUVA (psoralen + exposure to UV)
methotrexate, cyclosporin, apremilast
TNF inhibitors

8. Treatment of Psoriatic Arthritis:
NSAIDs to alleviate symptoms in mild involvement
Intraarticular corticosteroid injections
DMARDs considered early in disease, if fail,
TNF inhibitors - infliximab, adalimumab, etanercept