Eczema & Psoriasis

Overview

Background

Atopic eczema (also known as atopic dermatitis) is a very common inflammatory skin condition.(Guidelines 2006) It is characterised by an itchy red rash that typically tends to involve the skin creases (e.g. behind the knees, folds of elbows, around the neck), and is usually relatively mild.(Emerson 1998) In the acute stage, eczematous lesions are poorly defined and red with oedema, vesicles, and weeping. In the chronic stage, lesions are marked by skin thickening.

The condition is most commonly seen during childhood: in the UK, it affects around 15-20% of school-age children at some stage, but also affects some 2-10% of adults.(Kay 1994; Williams 2000; Poyner 2001) Most of those affected have relapses and remissions over months or years.(Williams 2000) Although childhood atopic eczema is usually mild, itching, pain and discomfort, loss of sleep, and limitation of activities can disrupt everyday life, including schooling, and can cause considerable distress for children and their families.(Barnetson 2002) The causes of eczema are not well understood and are probably due to a combination of genetic and environmental factors(Cookson 2002), such as house dust mites,(Van Bever 2002) pollution,(Polosa 2001) and prenatal or early exposure to infections.(Kalliomake 2002)

Conventional treatments include emollients (as creams, ointments or bath oils), topical corticosteroid creams, and calcineurin inhibitors (tarcrolimus and pimecrolimus). Also, patients should be advised to avoid contact with soaps and detergents, and limit exposure to possible exacerbating factors such as house dust mite, furry animals, extremes of temperature and, in hypersensitive individuals, certain foodstuffs.(McHenry 1995; Poyner 2001)

Psoriasis (chronic plaque psoriasis, or psoriasis vulgaris) is a chronic inflammatory skin disease. It is characterised by well-defined red, scaly plaques on the extensor surfaces of the body (e.g. knees, elbows, hands sacrum) and scalp.

The condition affects about 2% of people in the UK. In some patients, symptoms are mild, while in others they can cause physical, social and psychological disability. The course of the condition varies widely, with flare-ups and remissions. The cause of psoriasis is not known, but there is a genetic component, with around 30% of people having a family history of the disease. Also, emotional stress, physical trauma, acute infection, and some drugs can provoke or exacerbate the condition. (RCGP 1991; Naldi 2005) Excessive alcohol consumption and smoking may also be risk factors. (Poikolainen 19990; Monk 1986; Williams 1994)

Conventional treatments include topical treatments such as vitamin D and vitamin A derivatives, dithranol cream, coal tar preparations, topical corticosteroids, psoralen and ultraviolet light therapy (PUVA), and systemic treatments such as methotrexate, ciclosporin, acitretin and biologics (e.g. infliximab, etanercept).

Clinical evidence

There are few published randomised controlled trials (RCTs) of the effects of acupuncture in the treatment of chronic inflammatory skin conditions such as atopic eczema and psoriasis. Two small RCTs found that acupuncture reduced itch in patients with atopic eczema (Pfab 2011; Pfab 2010). On the other hand, a small RCT of acupuncture for psoriasis concluded that classical acupuncture is not superior to sham acupuncture (Jerner 1997). Sham interventions are not inactive placebos, but effectively different versions of acupuncture, so their value in evaluating treatment efficacy is highly questionable. (see Table below)

Potential mechanisms

In general, acupuncture is believed to stimulate the nervous system and cause the release of neurochemical messenger molecules. The resulting biochemical changes influence the body’s homeostatic mechanisms, thus promoting physical and emotional well-being. Stimulation of certain acupuncture points has been shown to affect areas of the brain that are known to reduce sensitivity to pain and stress (Hui 2010)

Acupuncture may help to relieve symptoms in people with atopic eczema and psoriasis by:

• Reducing inflammation, by promoting release of vascular and immunomodulatory factors (Zijlstra 2003; Kavoussi 2007);
• regulating mediators of the allergic reaction to extrinsic allergens, for example Ig-E (Rao 2006), serum cytokines (IL-2, IL-4, IL-10, IFN-, Ig-E) (Okumura 2002), and basophils (Pfab 2011);
• enhancing natural killer cell activities and modulating the number and ratio of immune cell types (Kawakita 2008);
• increasing local microcirculation (Komori 2009), which aids dispersal of swelling;