Psoriasis

Psoriasis is a chronic inflammatory condition of the skin which affects 2% of the population and causes an increase in the rate of the cell turnover. The normal rate of cell turnover is around a month but in psoriasis, it can be as little as 3-4 days. This causes a build-up of skin cells which cannot be shed normally and typically presents as well-demarcated pink or red plaques with a superficial silvery scale.

The plaques tend to be symmetrical and most often occur on the knees, elbows and shins but can occur anywhere on the body. The scalp and flexures of the axillae (armpits) and groin may also be affected. Psoriasis can also affect the nails which classically have tiny depressions or pits and with separation of the distal nail margin from the underlying nail plate and may be associated with arthritis (joint pains).

Psoriasis is due to an immune system dysfunction and is not something you can catch nor is it contagious. It is mediated by T-cells, a class of white blood cells which usually fend off attacks from viruses and bacteria, but with psoriasis the T-cells attack the healthy skin stimulating the increased production of new skin cells and causing inflammation.

The cause of the T-cell malfunction is thought to be a  genetic predisposition and environmental factors. There is often a positive family history of psoriasis and the environmental causes include:

• Infection: especially a streptococcal sore throat which can trigger the onset of psoriasis and precede subsequent flares.
• Stress: this can trigger or aggravate psoriasis.
• Medication: prescribed medication for high blood pressure such as beta blockers can be associated with psoriasis as can Lithium and stopping strong oral or topical steroids.
• Alcohol: excess alcohol intake is associated with bad psoriasis.
• Obesity
• Smoking
• Trauma: psoriasis plaques localize to areas of skin trauma such as a scar. The medical term for this is called Koebnerisation.

Psoriasis is a chronic disease that flares and subsides intermittently over life. While there is no cure for psoriasis (meaning the condition cannot be eradicated completely so a future flare-up never occurs), there are many ways to manage the symptoms.

Psoriasis is a chronic disease that flares up and subsides intermittently. While there is no cure for psoriasis (meaning the condition cannot be eradicated completely so a future flare-up becomes impossible), there are many ways to manage the symptoms.

Of the three main types of treatments for psoriasis -topical, light therapy (phototherapy) and medication, medication is the strongest and used for the most severe cases of psoriasis or those which have not responded satisfactorily to topical treatment +/- phototherapy.

Medication is either oral or by injection and although very effective at treating psoriasis, it comes with potential major side effects and is therefore reserved for the more serious cases. The majority of patients find that the gentler topical and light therapy treatments control their psoriasis satisfactorily.

Topical Treatments for psoriasis include:

•    Emollients and Moisturizers: regular use of emollients and moisturizers help soften psoriasis scale and increase moisturization of the skin, improving the scaly, dry and irritating feeling of psoriasis.

•    Keratolytic Agents: these can be used to treat thicker scale psoriasis and psoriasis on the feet They may contain ingredients such as urea (5-40%), salicylic acid (0.5-10%) and propylene glycol (up to 20%).

•    Topical Steroids: these are generally safe and help with the treatment of plaque psoriasis, scalp psoriasis, sebopsoriasis and flexural psoriasis, as well as psoriasis that affects the palms and soles. Topical steroids can be used in combination of other compounds such as calcipotriol, salicylic acid or antifungal agents.

•    Vitamin D Compounds: these can be used once or twice per day to reduce the redness and thickness of scaling, and include compounds such as calcipotriol, calcitriol and tacalcitol.

•    Tar: coal tar is used in many variations to treat psoriasis. It can be applied as a cream, shampoo, lotion, ointment or gel.  It is most suitable for small plaque and guttate psoriasis when used on the body. It can be irritating to the skin and messy, causing staining to body, clothes and hair, so care is to be taken when selecting and using tar for treatment.

•    Dithranol: is also called anthralin, is now mostly prescribed as Dithrocream and can be effective for the treatment of chronic plaque psoriasis. It does temporarily stain the skin and permanently stain clothes.

•    Calcineurin Inhibitors: these are used off-license to treat psoriasis, as their main treatment is for atopic dermatitis.

•    Tazarotene: this is a topical retinoid which can be applied once daily to plaque psoriasis. A common side effect is local irritation.

•    Light therapy (phototherapy) is noninvasive but there is a limit on the number of treatments one can have over a lifetime as excess sun exposure is known to be associated with certain skin cancers.

Types of light therapy for psoriasis include:

•    Narrowband Ultraviolet B: concentrated ultraviolet B light that treats psoriasis with multiple short exposure three times weekly treatments over six weeks.

•    Psoralens Plus Ultraviolet A: this treatment combines a medication (psoralens) which increases light sensitivity with UVA light exposure in a twice-weekly treatment regime often used for more severe cases or those who have not responded satisfactorily to UVB.

•    Controlled Sunlight Exposure: the goal of controlled light exposure is to reduce inflammation and slow new skin cell production; this is the easiest and most basic form of light therapy for psoriasis, but should not be taken on without direction and guidance from a doctor.

Psoriasis is a chronic disease that flares and subsides intermittently. While there is no cure for psoriasis (meaning the condition cannot be eradicated completely so it can be guaranteed there will never be a future flare) there are many ways to manage the symptoms.

There are three main types of treatment for psoriasis:

       1.Topical

       2. Light therapy

       3. Medication

Topical treatment is best suited for mild to moderate cases of psoriasis and consists of creams, ointments or gels.  Sometimes topical treatment will be used as a supplement to a larger medical plan for severe psoriasis.

Types of topical treatments for psoriasis include:

• Emollients or moisturizers to moisturize dry skin, reduce scaling and relieve itching. These are first-line treatment and can be used with other psoriasis treatments.

• Topical steroids work by reducing skin inflammation. Mild strength topical steroid creams can be useful for flexural and facial psoriasis but their use needs to be monitored as they can cause skin atrophy (thinning ) if overused.

• A topical steroid with a Vitamin D analogue such as Dovobet is a good treatment for plaque psoriasis on the body.

• Vitamin D analogues such as calcipotriol can be used on the face and for flexural psoriasis, help regulate the immune response to slow down the rate of cell turnover.

• Coal Tar slows down the rate of cell turnover and has been a treatment for psoriasis for many years but has a distinctive smell, stains clothes and is now mostly used for widespread small plaque psoriasis or guttate psoriasis characterized by widespread small patches of inflamed skin.

• Dithranol is another well-established treatment for thick plaques of psoriasis on the limbs. It is now mostly used with a short contact regime of gradually increasing concentrations of Dithrocream. It also stains clothes.

• Calcineurin inhibitors such a Tacrolimus or Pimecrolimus originally developed to treat eczema and used on the face and for flexural psoriasis.

Phototherapy

Psoriasis often improves in the summer and on exposure to sunlight. Light Therapy, also known as phototherapy, harnesses the power of ultraviolet light often in combination with topical treatment if topical treatment alone has not been effective.

Types of light therapy for psoriasis include:

• Narrowband ultraviolet B
• Psoralens plus ultraviolet A or PUVA which combines a light-sensitizing medication with ultraviolet light treatment.

Your doctor always chooses the most appropriate treatment for you in consultation and taking into account your wishes.

Systemic Medication

Systemic treatment for psoriasis through medication is typically reserved for severe cases or those which have not responded to topical treatments with phototherapy. This is because medication to treat psoriasis are accompanied by potentially severe side effects.

Your doctor may prescribe a psoriasis medication for a short burst and supplement with other treatment types. It is important to discuss a medication plan thoroughly with your doctor.

Psoriasis medications are either taken orally via pill or by injection.

Types of these medications include

• Methotrexate (oral pill)
• Cyclosporin(oral pill)
• Biologics (injections)