Psoriasis is a skin disorder characterized by the presence of scaly plaques on the surface of the elbows, knees, scalp, and lower back and even on the penis. More advanced cases of psoriasis can involve the joints and eyes as well. There are different kinds of psoriasis but in this article we shall cover the general aspects, clinical features, diagnosis and management of this condition.
Psoriasis is not a very common condition with only around two in 100 people in the US suffering from it. It appears to be more common in women and less common in dark skinned individuals.
The skin is made of an outer layer called the epidermis which consists of cells called keratinocytes. Excessive growth of the cells is what results in psoriasis.
Some of the common causes of psoriasis include:
1. Genetic factors – It appears that psoriasis may run in families.
2. Environmental factors – Psoriasis can sometimes be triggered by cold temperatures, infections, drugs (beta-blockers, lithium) and alcohol use.
3. Autoimmune causes – There is evidence to suggest that psoriasis may occur due to excessive activity of T-cells in the skin.
Patients who suffer from psoriasis classically demonstrate a large scaly rash present in multiple extensor sites of the body (elbows, knees, and scalp). Patients may provide a history of a similar rash in a family member or may have suffered a recent infection before noticing the rash. In addition patients may complain of joint pains and change
in the appearance of the nails. On rare occasions there may be involvement of the eyes.
Upon examination patients have a classic maculopapular rash or scaly plaques which are erythematous at the base but silvery on the surface. The rash is clearly demarcated without evidence of underlying infection such as raised temperature. But different forms of psoriasis can present in different ways. In some cases, Auspitz’s sign is positive.
Severe Psoriasis – Patients with psoriasis may have involvement of the nails which can appear in the form of pitting and yellowish discoloration. Some patients also suffer from psoriatic arthritis which involves the hands and feet and sometimes larger joints.
Classic psoriatic rash
Psoriasis of the scalp
Diagnosis of psoriasis is often made from clinical history and following clinical examination. Confirmation of the diagnosis using specialised tests is rarely required unless the rash appears atypical and other clinical conditions that cause a similar rash need to be ruled out. Skin biopsy may show excessive skin keratinisation along with the
presence of ‘clubbed rete pegs’.
These can be listed as follows:
1. Lifestyle changes – Exposure to sunlight, relaxation therapy and
application of moisturisers. These are extremely beneficial in mild cases.
Stress management can help reduce flare ups as well. Lifestyle changes are a
part of alternative therapies.
Suggestions have been made that avoiding a non-vegetarian diet, or consuming cod liver oil supplements regularly can prevent flare ups, though there is no strong evidence backing this fact. Simple measures such as decreasing alcohol intake, stopping smoking and getting regular exercise have been stated to improve psoriasis as well. Vitamin supplementation may also help.
Acute flare ups can sometimes require immediate relief, and products such as petroleum jelly and regular moisturisers can help rejuvenate the skin and help reduce any inflammation present.
2. Coal tar application – These are easily available over the counter.
They work by reducing the rate of division and growth of the skin cells, just
reducing the size of the plaque. It is ideally avoided in case there is evidence
of severe inflammation or bleeding from the plaques.
3. Ultraviolet light treatment (phototherapy) – Treatment with psoralen ultraviolet –A (PUVA) is useful in managing patients with psoriasis. This consists of a combination of topical or oral psoralen (Methoxsalen) with ultraviolet – A light. It is believed that PUVA helps reduce the growth rate of the keratinocytes in the epidermis. However, care should be taken with these treatments as it can increase the future risk of developing malignant melanoma or squamous cell cancer of the skin.
UV light chamber
Narrow band ultraviolet light B (UVB) has also been found to be extremely useful. There are two separate treatment regimes that may be adopted when using UVB –
- Goeckerman regimen – Coal tar application followed by UVB exposure. Produces an excellent improvement in most patients.
- Ingram method – Coal tar followed by UVB followed by anthralin administration.
4. Topical steroid creams (such as Triamcinolone and Clobetasol) have been shown to have some benefit, and are best used along with coal tar preparations. However, oral steroids should ideally be avoided, as following a treatment course, withdrawal of steroids can lead to another flare up which can make treatment difficult.
5. Oral medications – These are generally offered to patients in whom severe psoriasis is a problem. The drugs include
- Oral retinoids
The former 2 are immunosuppressive agents while oral retinoids are vitamin A analogues useful in managing skin conditions. They are particularly useful if patients have joint involvement in psoriasis.
6. Newer agents – These days, newer biological agents have been developed that act against the T cells and thus alter the immune process leading up to development of psoriasis. While they can be used for skin disease, like the oral agents above, they are reserved for more complicated psoriasis that involves the joints.
There is unfortunately no cure. Treatments are only aimed at managing symptoms and preventing acute flare ups. Mild cases of psoriasis rarely cause serious problems. However, more recent evidence suggests that patients who suffer from psoriasis are at a higher risk of developing heart attacks and angina. In addition, large plaques in psoriasis can be cosmetically unpleasant and can have a detrimental effect on a patient’s confidence, especially if they are in exposed areas of the skin.
Psoriasis is a chronic skin condition that unfortunately has no cure. However, there are a number of safe treatment options that allow for prevention of acute flare ups, making the disease manageable to most patients.