Psoriasis is a chronic recurrent dermatosis characterised by sharply demarcated patches and plaques involving the scalp, trunk and extremities. It is a common skin disease which affects about 2% of the population.
1. an immune mediated process with activation / stimulation of Tlymphocytes
2. an increase cell turnover with epidermal hyperproliferation
3. polygenic inheritance with variable penetrance
1. streptococcal infection, stress, drugs eg. antihypertensives, antimalarials
3. excessive smoking/alcohol consumption
-erythrodermic psoriasis ->90% of the skin appears red with scaling.
-guttate psoriasis- occurs commonly in children and is usually preceeded by a
-sites of predeliction include the scalp, retroauricular area, knees, elbows, lower back, nails and joints.
What are the treatment options available?
-aim is for combination /rotational/ sequential therapies
1. Tar preparations eg polytarr shampoo, crude coal tar
2. Topical steroids –reserved for facial, scalp and flexural psoriasis
3. Vitamin D analogues eg . Dovonex
4. Topical keratolytics eg. Salicylic acid
5. Anthralin derivatives eg Dithranol therapy
6. Topical retinoids eg. tazorotene (Zorac cream/gel)
1. PUVA therapy
2. Narrowband UVB (TL01 lamps)
3. Excimer laser –for localised plaque psoriasis
1. Methotrexate – works by inhibiting cell turnover and thereby reduces cell proliferation in psoriasis.
2. Acitretin eg Neotigason
1. These are therapeutic molecules that are specifically targeted in order to imitate or inhibit naturally occurring
2. The biologics work by blocking the development of the disease rather than treating the consequences of an
abnormal immune function.
3. These agents have the advantage of being given as a single agent and by injection
1. This is a type of biologic that blocks a molecule responsible for the inflammation seen in psoriasis and
psoriatic arthritis. It is called Tumour necrosis factor (TNF).
2. This drug blocks TNF from binding with TNF receptor thus neutralising it. It is injected intravenously at
various time intervals.
1. This biological agent is a TNF receptor blocker. It is a fusion protein and is approved for the treatment of psoriatic arthritis as well as extensive cutaneous psoriasis. It is injected subcutaneously which can be done by patients at home initially twice a week for three months and then less frequently. The onset of action is rapid within 2-3 weeks.
1. This is the first TNF alpha blocker that is entirely of human origin. It is also administered by subcutaneous