Psoriasis

Psoriasis is a common, chronic, relapsing, inflammatory skin disorder. Psoriasis has a genetic basis and can affect the skin the nails and also joints.

Psoriasis has a tendency to wax and wane.

Flares can be related to systemic, environmental factors, or infection.





Psoriasis most commonly manifests itself on the skin of the elbows, knees, scalp, and lumbosacral areas.



Most psoriatic nail disease occurs in people with clinically evident psoriasis.


Psoriatic arthritis is a chronic inflammatory arthritis that is commonly associated with psoriasis.



Frequency

Approximately 2-3% of people are affected by psoriasis

At least 5% of patients with psoriasis develop psoriatic arthritis

Sex

Psoriasis is slightly more common in women than in men


Symptoms of Psoriasis

The surface of psoriatic lesions often has a layer of dead skin cells that appear as silver scales.

Erythematous(Red) scaly area which can have a sudden onset.

Scaling plaques that itch.

Lesions may be vesicular.

Joint Pain.



Joint Findings

Sausage Digits

Enthesopathy- An inflammation of the insertion points of tendon into bone.

Tendonitis


Nail Findings

Oil drop - a translucent, yellow-red discoloration in the nail bed resembling a drop of oil beneath the nail plate.


Pitting- Pitting is a result of the loss of cells from the surface of the nail plate.


Beau lines- These lines are transverse lines in the nails


Leukonychia- Leukonychia is areas of white nail plate.


Onycholysis Onycholysis is a separation of the nail plate from its attachment to the nail bed.



Causes


Psoriatic lesions are caused by an increase in the skin cells turnover rate.

Genetic factors- Approximately 40% of patients with psoriasis or psoriatic arthritis have first-degree relatives who are affected.

Psoriatic nail disease may be due to a combination of genetic, environmental, and immune factors.



Differentials

• Seborrheic dermatitis
• Onychomycosis
• Squamous cell carcinoma
• Nummular eczema
• Lichen planus
• Lichen simplex chronicus
• Pustular eruptions

Arthritic Differentials

• Gout
• Osteoarthritis
• Rheumatoid arthritis
• Septic arthritis

Work Up


Radiographs of affected joints can be help differentiate the type of arthritis.

Psoriatic arthritis- The diagnosis is based primarily on clinical and radiographic findings.

Nail biopsy- A nail biopsy may be obtained to confirm the diagnosis of nail psoriasis



Laboratory studies

Rheumatoid factor (RF)- negative

Erythrocyte sedimentation rate (ESR)- usually normal

Uric acid level- May be elevated in psoriasis





Treatment

Skin Lesions

Topical corticosteroids- Used to reduce plaque formation.


Coal tar- Coal tar is an inexpensive treatment that is available over the counter in shampoos or lotions for use in widespread areas of involvement..

Keratolytic agents- Used to remove scale, to smooth the skin, and to treat hyperkeratosis


Psoriatic arthritis

Nonsteroidal anti-inflammatory drugs- (NSAIDs)

Disease-modifying antirheumatic drugs (DMARDs)

Anti–tumor necrosis factor (TNF)-alpha medications.

Nails
Avulsion therapy -can be used as an alternative therapy for psoriatic nail disease.