Phytotherapy for atopic dermatitis - eczema - Phytotherapy Review & Commentary

Townsend Letter for Doctors and Patients, May, 2003 by Kerry Bone

Introduction

The treatment of skin disorders in phytotherapy draws heavily on traditional considerations. These can be represented as follows:

* Skin disorders (other than outright infections or injury) are indicative of deeper metabolic imbalances. Hence the use of topical agents, as relied upon heavily in conventional dermatology, is of limited value and represents only a superficial approach which is essentially based on symptom control. (This is not to say that topical herbal treatments are without value in skin disorders, just that they are employed judiciously as only part of an overall strategy.)

* Skin lesions are manifestations of a greater disease process. Given that skin disorders involve unspecified disordered metabolism at a deeper level, the use of agents which can effect a change in these processes is required. These agents are known as alteratives or depuratives (see below). They are probably the most mysterious agents used in Western herbal therapy.

* As well as depuratives, other agents which assist the various detoxification mechanisms used by the body can be indicated to remove toxic accumulations and achieve a restoration of normal metabolism and immune function.

* Attention to lifestyle and diet is an important part of the treatment program, which is based on treating the patient as a whole (and as an individual).

In many cases the skin lesion is a valid attempt by the body to discharge or metabolize toxic agents. Hence chemical treatment aimed at suppressing (as opposed to judiciously controlling) this process will ultimately be counter-productive.

From the above it is clear that the phytotherapeutic treatment of skin disorders is largely aimed at the cause, whatever that might be. Fortunately, recent scientific research is revealing new information about the causes of certain skin diseases - especially eczema (atopic dermatitis). Such relevant information will be included in this review.

Herbal Actions

Before covering the herbal approach to eczema, it is useful to briefly review some of the herbal actions which are particularly relevant for dermatological conditions.

Depuratives/Alteratives

Depuratives, otherwise known as "blood cleansers" or "alteratives," are employed to effect a gradual change in chronic disease states, especially skin, joint and the connective tissue disorders. They are said to act by improving the processes of detoxification and elimination, hence they can be expected to act only slowly. Progress can be measured over months, rather than days or weeks.

The main depuratives are Arctium lappa (burdock), Mahonia aquifolium (Oregon grape), Trifolium pratense (red clover), Galium aparine (cleavers), Rumex crisp us (yellow dock), Scrophularia nodosa (figwort), Viola tricolor (heartsease), Smilax species (sarsaparilla), Solanum dulcamara (bittersweet) and Iris versicolor (blue flag).

However, herbs with an action on the immune system, such as Echinacea species and Phytolacca and choleretic herbs including Taraxacum officinale (dandelion), Cynara scolymus (globe artichoke), Fumaria officinalis (fumitory) and Berberis vulgaris (barberry) are also regarded as possessing some depurative activity.

Anti-allergic Herbs

Herbs with anti-allergic properties are used for symptom control or relief, especially in eczema and urticaria. They include Albizia lebbeck, Scutellaria baicalensis (Baical skullcap) and Urtica dioica (nettles). They are generally taken internally, although Albizia can be applied topically.

Anti-inflammatory Herbs (internal use)

Anti-inflammatory herbs are mild agents which can help to control (but not suppress) symptoms while longer-term strategies involving depuratives and addressing the causes take effect. Their use will help keep the patient encouraged to continue with the treatment. They include evening primrose oil, Bupleurum falcatum, Glycyrrhiza glabra (licorice), Rehmannia glutinosa and Centella asiatica (gotu kola).

Anti-inflammatory Herbs (topical use)

These include Calendula, Matricaria chamomilla (Chamomilla recutita or German chamomile), Stellaria media (chickweed), Glycyrrhiza glabra (licorice), Hamamelis virginiana (witch hazel) and Aloe barbadensis (Aloe vera) as well as the emollient activity of herbs containing mucilages such as marshmallow root.

Definition

Eczema, or dermatitis, is a pruritic inflammatory skin reaction that manifests with variable clinical and histologic pictures. Atopic dermatitis is a dermatitis which is linked to the atopic state. The patient is much troubled by itching skin and there is a history of chronic or chronically relapsing dermatitis, worst on the flexures, and a family or personal history of atopy (asthma, hayfever, urticaria etc).

Pathogenesis

Factors involved in the etiology or pathogenesis of atopic dermatitis are discussed below.

a) Family History

Atopic syndrome is genetically determined and is associated with high plasma levels of IgE. When both parents have the same atopic disease, their child has about a 70% risk of expressing this disease. However, the increasing prevalence of atopic dermatitis is difficult to explain on the basis of genetics alone. (1)