Eczema

Synonyms :  

Clinical features, Diagnosis, Management, Prognosis,

The terms eczema and dermatitis are now used synonymously. They refer to a distinctive reaction pattern of the skin showing a combination of signs which depends on the duration and type of eczema. There are two groups of eczema: exogenous (or contact) and endogenous (or constitutional). While overlap between the two groups is common, distinction between them is critical for treatment and prognosis.

The classification of eczema:

Exogenous (Contact) Eczema

1. Irritant contact eczema

This is nonimmunologically mediated inflammation of the skin. Industrial detergents, alkalis, acids, solvents and abrasive dusts are common causes, and consequently irritant eczema accounts for the majority of industrial cases and work loss. The elderly, those with fair, dry and sensitive skin and those with an atopic background (personal or family history of asthma, hay fever or atopic eczema) are especially vulnerable. Nappy eczema (rash) in babies is common and due to irritant ammoniacal urine and faeces. Strong irritants (e.g., acids, alkalis, phenol) elicit an acute reaction on the site of contact whereas weak irritants (e.g., soaps, detergents) most often cause chronic eczema, especially of the hands, after prolonged exposure. In certain patients sun exposure aggravates irritant contact dermatitis and this variant is then called phototoxic contact dermatitis.

2. Allergic contact eczema

This is due to a delayed hypersensitivity reaction (Type IV) following contact with antigens or haptens (incomplete antigens which must combine with certain protein carrier molecules in order to act as antigens). Previous exposure to the allergen is required for sensitisation and the reaction is specific to the allergen or closely related chemicals. Common allergens are nickel (e.g., jewellery), dichromate (e.g., leather, cement), rubber chemicals (e.g., shoes, tyres), paraphenylenediamine (e.g., in hair dyes), topical antibiotics (e.g., neomycin, penicillin), topical antihistamines, cosmetics (e.g., nail polish, deodorant), airborne substances (e.g., pollen, insecticide spray), plants like poison ivy and many others. If skin lesions occur only after exposure to sun, allergic contact dermatitis is called photoallergic contact dermatitis.

The eczema reaction occurs wherever the allergen comes in direct contact with the skin, but after a delay period of several hours to 2 days. There are many easily recognisable patterns, e.g., eczema of the earlobes, wrists, fingers, neck and back due to contact with nickel in jewellery, watches and bra clips; eczema of the hands and wrists due to rubber gloves, which help in establishing the correct diagnosis.

Endogenous Eczema

1. Atopic eczema (Neurodermatitis)

Atopy is a genetic predisposition to form excessive amounts of IgE antibodies to inhaled, injected and ingested antigens and to develop one or more diseases such as asthma, hay fever, urticaria (hives), food and other allergies and this distinctive form of eczema. Atopic eczema is common, affecting 3% of all infants, and runs a chronic course with variable exacerbations and remissions. It normally clears during adolescence or adulthood but may continue into adult life as a chronic disease. In most cases of atopic eczema allergic base can not be established, and the allergens remain undiscovered. In others various inhaled or food allergens may be relevant. Emotional stress (neurodermatitis!), temperature or humidity changes, fragrances, laundry detergents, fabric softeners, soaps, house dust mites in bedding and carpeting and wool clothes commonly cause exacerbations. In most patients the rash characteristically develops on the backs of the knees, fronts of the elbows, wrists and ankles, but also around neck and in the inguinal area.

2. Seborrhoeic eczema

Despite the name, the composition and flow of sebum are usually normal. Its cause remains unknown though the yeast-like fungus, Pityrosporum, appears to be a perpetuating factor by breaking down oil in sebum. In infants it is known as ‘cradle cap?but it is rarely seen in children beyond infancy. The lesions appear as scaly, white or yellowish plaques on erythematous background with mild pruritus (itching). Commonly involved areas are scalp (dandruff), ears, face, eyebrows, presternal and interscapular skin, flexures of axillae, umbilicus, breasts and groin.

The incidence and severity of disease seem to be affected by genetic factors (the condition often runs in families), emotional or physical stress and climate (it is usually worse in winter). The prognosis is better than in atopic dermatitis, and treatment is usually more effective.

Clinical features:  < BACK TO TOP >

Diagnosis:  < BACK TO TOP >

       Carefully taken history coupled with physical examination often suggest correct diagnosis.

       Patch testing to allergens is used in suspected cases of allergic contact eczema. Patch testing to irritants (which cause some reaction in everybody) is not advised. Standard dilutions of the test substance are applied to the back under aluminium discs and the patches secured in place with sticky tape for 48 hours. The sites are inspected for eczematous reactions after removal and after a further 48 hours.

       Prick testing is used for a few patients with stubborn atopic eczema if food or inhalant allergens are suspected as exacerbating factors. It detects immediate (IgE mediated - Type I) hypersensitivity. Commercially prepared dilute antigens and a control are placed as single drops on the volar aspect of the forearm. Skin pricks through the drops are carried out using a sterile needle for each test and without drawing blood, and after all drops are removed with a tissue the sites are inspected 10 minutes later for wheal and flare reactions.

       The radio allergosorbent technique (RAST) is a blood test which can detect IgE antibodies against certain allergens and is much safer.

Management  < BACK TO TOP >

       Explanation, reassurance and encouragement are very important.

       Avoidance of contact with irritants or allergens if identified is advised, sometimes a change of job must be done, patients with phototoxic or photoallergic contact dermatitis should also avoid unnecessary sun exposure.

       In acute eczema gauze or thin cloths dipped in cold water and applied to lesions are soothing and cooling.

       The careful use of topical steroids may be considered; lotions and creams are preferable in acute eczema and ointments in chronic cases (e.g., hydrocortisone [Cortaid, Dermacort, Egocort, Sigmacort], betamethasone [Diprosone, Betnovate, Celestone], triamcinolone [Aristocort], mometasone [Elocon]).

       The side effects of strong or extensive local steroid therapy should always be borne in mind in patients applying these preparations for years. They include skin thinning (with striae, fragility and purpura) and sometimes systemic side effects after absorption (Cushingoid features).

       In chronic eczema regular moisturising is of great value because affected skin can not preserve water and dry skin tends to be itchy (soaking in water, e.g., bathing, and then application of a protective cream, or frequent application of moisturisers such as Aqueous cream, Sorbolene cream or Q.V. lotion, various bath oils that can also be applied directly to wet skin); soaps should be avoided since they tend to cause irritation, non-irritant alternatives such as Q.V. wash should be used instead.

       Oral antihistamines may be of value to relieve itching (e.g., promethazine [Phenergan], terfenadine [Teldane], cetrizine [Zyrtec], fexofenadine [Telfast], azatadine [Zadine] and loratadine [Lorastyne, Claratyne, Clarinase]).

       In severe cases oral corticosteroids may be needed (e.g., prednisone [Panafcort, Sone, Deltasone], prednisolone [Delta-Cortef, Panafcortelone, Solone] or methylprednisolone [Medrol, Solu-medrol, Depo-medrol]).

       Dandruff in seborrhoeic dermatitis usually responds to selenium [e.g., Selsun Blue 5] and tar [Alphosyl, Alpha Keri Tar] containing shampoos or shampoos with ketoconazole [Nizoral, Sebizole] or miconazole [Hairscience anti-dandruff shampoo].

       In babies cradle cap may be treated with topical application of 6% salicylic acid in olive and castor oil [Egozite lotion] at bedtime for 3-5 days to soften the scales that are later removed with a gentle wash. For more stubborn cases 1% hydrocortisone gel can be rubbed in twice daily.

Prognosis  < BACK TO TOP >

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Nutrition  < BACK TO TOP >

Nutrition that alleviate or prevent eczema :-
Calcium, Potassium, Selenium, Silicon, Sulphur, Biotin, Inositol, Para Aminobenzoic Acid (PABA), Vitamin A, Vitamin B2, Vitamin B6, Vitamin B12, Vitamin C

Herbs  < BACK TO TOP >

Herbs that alleviate or prevent eczema :-
Herbs - Achillea millefolium (Yarrow), Albizia lebbeck (albizia), Arctium lappa (Burdock), Berberis aquifolium (oregon grape), Calendula officinalis (Calendula), Echinacea spp (echinacea), Fumaria officinalis (fumitory), Galium aparine (clivers), Ginkgo biloba (Ginkgo), Glycyrrhiza glabra (Licorice), Hydrastis canadensis (Goldenseal), Iris versicolor (blue flag), Plantago lanceolata (ribwort), Rumex crispus (Yellow dock), Schisandra chinensis (Schizandra), Scrophularia nodosa (figwort), Scutellaria baicalensis (baical skullcap), Tabebuia impetiginosa (Pau D'Arco), Trifolium pratense (red clover), Urtica dioica folia (nettle leaf), Urtica dioica radix (nettle root), Viola tricolor (heartsease)
Topical - Chamomile, Glycyrrhiza glabra (Licorice), Sangre de Grado, Sassafras, Witch Hazel
Tea - Chaparral, Red Clover, Sarsaparilla
Dietary Oils - Borage Seed Oil, Evening Primrose Oil, Fish Oils, Flax Seed Oil, Olive Oil
Topical Oils - Emu Oil, Lavender, Neem Oil, Oregano Oil, Tea Tree Oil

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