The Skin System|
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
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
2. Allergic contact eczema
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.
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.
1. Atopic eczema (Neurodermatitis)
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
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.
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 >
taken history coupled with physical examination often suggest correct
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
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 >
reassurance and encouragement are very important.
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.
acute eczema gauze or thin cloths dipped in cold water and applied to lesions
are soothing and cooling.
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]).
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).
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.
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]).
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]).
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
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 >
Nutrition < BACK TO TOP >
Nutrition that alleviate or prevent eczema :-
Herbs < BACK TO TOP >
Herbs that alleviate or prevent eczema :-
(source : -)
speaker Mr NgThian Watt the Principal Trainer from
Napoleon Hill Associates MalaysiaDetails