Psoriasis is a common chronic skin disease characterised by cutaneous inflammation and epidermal hyperproliferation - lesions appear on any part of the skin, but particularly the scalp, sacral area, and over the extensor aspect of the knees and elbows
the major manifestation of psoriasis is the chronic skin disease (although psoriatic joint disease is another major morbidity associated with psoriasis)
psoriatic skin disease is characterised by cutaneous inflammation and epidermal hyperproliferation (normally cells of the epidermal layer renew every 28 days, but in psoriasis the regeneration occurs every 2 to 4 days) (1,2)
lesions appear on any part of the skin, but particularly the scalp, lumbosacral area and over the extensor aspect of the knees and elbows (3).
Characteristically, there are:
well-defined, raised, erythematous and scaly lesions (3), which are "salmon pink" or "full rich red" in colour
surface silvery scale which may be easily removed often leading to pin - point capillary bleeding (Auspitz sign) (4)
they may or may not itch but this is not usually a prominent feature
acute disease may manifest as inflammation and erythema while chronic lesions present as typical plaques (4). In most of the patients psoriasis presents in a chronic course with periods of remission (1).
psoriasis is an emotionally and physically debilitating disease which is often underestimated by medical practioners (4)
A strong genetic predisposition can be seen in psoriasis. Around 8 genetic susceptibility loci (PSORS I-VIII) have been observed (1). Psoriasis susceptibility 1 (PSORS1) locus located on the 6th chromosome is considered to be the most important one and can be seen in up to 50% of psoriasis cases (3).
NICE suggest (4):
psoriasis is an inflammatory skin disease that typically follows a relapsing and remitting course - prevalence of psoriasis is estimated to be around 1.3-2.2% in the UK.
is uncommon in children (0.71%) and the majority of cases occur before 35 years
is associated with joint disease in a significant proportion of patients (reported in one study at 13.8%)
plaque psoriasis is characterised by well-delineated red, scaly plaques that vary in extent from a few patches to generalised involvement
by far the most common form of the condition (about 90% of people with psoriasis)
other types of psoriasis include guttate psoriasis and pustular (localised or generalised) forms
distinctive nail changes occur in around 50% of all those affected and are more common in people with psoriatic arthritis
several studies have also reported that people with psoriasis, particularly those with severe disease, may be at increased risk of cardiovascular disease, lymphoma and non-melanoma skin cancer
first-line therapy describes traditional topical therapies (such as corticosteroids, vitamin D and vitamin D analogues, dithranol and tar preparations)
second-line therapy includes the phototherapies (broad- or narrow-band ultraviolet B light and psoralen plus UVA light [PUVA]) and systemic non-biological agents such as ciclosporin, methotrexate and acitretin
third-line therapy refers to systemic biological therapies such as the tumour necrosis factor antagonists adalimumab, etanercept and infliximab, and the monoclonal antibody ustekinumab that targets interleukin-12 (IL-12) and IL-23
A useful summary algorithm based on NICE guidance for management of psoriasis in adults has been produced (5). This is an excellent summary for management in primary care: