Psoriasis

1-3 % of the population has this disease. More common in Europe and North America. Often seen between 15 to 40 yrs.

Aetiology

Real aetiology is unknown. Genetic: If one parent is affected the offspring has 25% chance to develop the disease. If both parents are affected the chances rise to 60%.

Clinical Features:

Common Patterns of Psoriasis:

Plaque pattern : It tis the most common type. The individual lesions are well demarcated and are red with dry silvery white scaling. Most common sites involved are scalp, elbow, knee and lower back.
Guttate Psoriasis : Usually seen in the children and adolescents. The individual lesions of the rash are small and scaly. The bouts of guttate psoriasis clear in months but the patient may develop plaque pattern later.

Scalp : This site is often involved. Areas of scaling are interspread with normal scalp. Significant hair loss occurs only if there is gross involvement.
Nails : Involvment of nails is common. Thimble pitting, Onycholysis (separation of nail from nail bed), Subungal hyperkeratosis are main changes seen in the nails. Involment of nails reflect the extent of the disease elsewhere.
Flexures : Involment of flexures like axillary folds and submammary folds are not scaly but red, glistening and symmetrical.
Palms : Psoriasis in the palms are poorly demarcated and are poorly erythematous.

Less common types of psoriasis are Napkin psoriasis and Localised pustular psoriasis in the palms and soles consisting of numerous small serile pustules on erythematous base.

Complications : Psoriatic Arthropathy is seen in 5 %. There may be distal small joint involvement mainly terminal interphalangeal joints of hands and toes. Single large joint arthropathy may also be seen which mimmics rheumatoid arthritis. Sacroiliac joint and lumbar spine involvement may also be seen.

Treatment :

Coal Tar preparations : 100 % strong coal tar solution and 4 % tar paste are to be applied to the patches twicw daily. Salicylic acid 1-2 % may be added to the preparation to remove scaling.
Dithranol : 1-2 % dithranol cream is applied to the lesions for a duration of 30 minutes daily.
Coal tar and Dithranol preparation are best avoided on face, genitals and skin folds as they are irritating.
Topical Steroids : Their long term use is not indicated in most cases as on their withdrawal relapse may occur and the disease may change to unstable phase. Indications of their use are lesions of face, genitals and skin flexures where coal tar may be too irritant. Unresponsive lesions of scalp and soles may also need topical steroids.
Ultraviolet radiation : Natural sunlight has benificial effect. During winters medium wave ultraviolet radiation is helpful.
Systemic treatment : In extensive psoriasis which fails to repond with local measures may need to be put on systemic treatment considering the sideeffects as they have to be taken for long period. Psoralen, retinoids (etretinate), methotrexate have to be given along with local medication.

FDA OKs mousse to treat psoriasis

Patients who suffer psoriasis of the scalp won a
slightly different kind of treatment a mousse-like foam to
rub onto scalp lesions with less mess than traditional drugs. Until
now, the main treatment has been a lotion containing the chemical
betamethasone, but putting a lotion on the scalp every day is messy
and greasy. The Food and Drug Administration approved Connetics
Corp.'s new version of betamethasone, an easier-to-apply foam called
Luxiq. An estimated 3.5 million Americans have scalp psoriasis,
marked by redness, scaling, severe itching and irritation. In one
study of 172 patients, 72% treated with Luxiq had complete or almost
complete clearance of their psoriasis outbreak, compared with 47% who
used a betamethasone lotion. Connetics said Luxiq will be available
in about six weeks. A final price has not been set, but a spokeswoman
said it would be about $50 to $60 for a 100-gram bottle.

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