B. Wang, MD, FRCPC
Division of Dermatology, McGill University, Montreal, Canada
Definition of Eczema
Often used interchangeably with the term atopic dermatitis (AD).
- Is a broad-spectrum condition that is subdivided into different clinical presentations, i.e., infantile, childhood and adult.
- Eczema is a clinical diagnosis that must meet a set of diagnostic criteria: [Williams HC, et al. Br J Dermatol 131(3):383-416 (1994 Sep.).]
- Pruritus, plus 3 or more of the following
- Early age of onset
- Typical distribution (i.e., extensors in infants and children, flexures in adults)
- Personal or familial history of atopy (e.g., asthma, hay fever, eczema)
- Xerosis (dry skin)
- Chronicity and relapses
- Increased levels of IgE are not necessary to make the diagnosis.
- There are no diagnostic lab tests.
- The prevalence of eczema is increasing, especially over the past 30 years.
- Current studies find a prevalence of 20% in children in North America, Northern Europe, and Japan, [Laughter D, et al. J Acad Dermatol 43:649-55 (2000 Oct.)]. With lower figures elsewhere in the world, [Williams HC, et al. J Allergy Clin Immunol 103:125-38 (1999 Jan.)] though reasons for this remain unclear.
- There is a strong genetic component.
Presentation of Eczema
- Can either be acute or chronic in nature.
- Acute eczema shows marked inflammation of skin, erythema and juicy papules.
- Chronic eczema shows lichenification (thickening of the skin) from repeated rubbing or scratching, postinflammatory hyper- or hypopigmentation.
- Both types can show excoriations.
- There is commonly a secondary infection, usually with Staphylococcus aureus (S. aureus).
- Chronicity of disease must be emphasized – there is no cure for eczema.
- Preventative measures, including avoidance of trigger factors and skin hydration, are mainstays of treatment.
- Therapeutic measures include the use of topical and oral medications, and the treatment of secondary infections, if present.
- General strategy involves induction of remission, stabilization and maintenance, and the rescue of flares.
- Avoid irritants and allergens such as harsh detergents , wool or other itch-inducing fabrics, and common allergens such as pet dander, dust, smoke, and pollens.
- The trigger need not be allergic in nature to induce eczema.
- Need to be used on at least a daily basis because of the inherent xerosis of the skin.
- Moisturizers that are occlusive prevent water loss.
- Oils tend to stay on the surface of the skin and are not absorbed.
- Maintain hydration of the skin
- Use mild or soapless cleanser that does not disrupt the barrier of the skin.
- Warm, not hot, baths or showers are encouraged.
- It is crucial to moisturize immediately after bathing.
- Cool temperatures
- Sweat is aggravating to eczematous skin, and can promote pruritus.
- Most effective for an acute onset of eczema (flare) because of rapid onset of action.
- Potency of the agent depends on the location of the eczema (mild for face and groin, moderate for body).
- Use the lowest potency possible to control the flare.
- Greater potency exists when the drug is delivered as an ointment as compared to a cream or a lotion.
- Rarely, skin atrophy, tachyphylaxis (loss of effectiveness), or adrenal suppression is seen with prolonged, daily use. Use of more potent topical steroids is associated with increased risk of development of adverse effects. Risk is higher for younger children because of their surface area-to-weight ratio and because their skin is more permeable.
- To be applied only on the area of active disease.
- Can be used in combination with topical calcineurin inhibitors for local control of eczema.
- Allergic contact dermatitis to corticosteroids is rare.
Topical Calcineurin Inhibitors
- New class of anti-inflammatory agents, available as pimecrolimus 1% cream (Elidel®), and tacrolimus 0.03% (children 2–12 years) and 0.1% (adults) ointment (Protopic®).
- Calcineurin inhibitors block cytokine transcription mediated by NF-AT in T cells.
- Pimecrolimus is approved for short-term and intermittent long-term therapy of mild-to-moderate eczema, whereas tacrolimus is approved for therapy of moderate-to-severe AD.
- Both are excellent for long-term management of AD [Meurer M, et al. Dermatol 205(3):271-7 (2002); Hanifin JM, et al. J Am Acad Dermatol 53(2 Suppl 2):S186-94 (2005 Aug).]
- Reduces the intensity of the flare
- Helps maintain remission
- Pimecrolimus has been shown to increase the time between flares.[Meurer M, et al. Dermatol 205:271-7 (2002).]
- To be applied only on areas of disease.
- Most common side-effects are local burning and stinging of the skin, which are transient.
- In response to black box warnings for calcineurin inhibitors initiated by Health Canada and the US FDA, the Canadian Dermatology Association has stated that the topical use of calcineurin inhibitors does not lead to an increased risk of malignancy, specifically lymphoma, and so can be used with the same precautions as with topical corticosteroids.[Maddin S. Skin Therapy Lett10(4):1-3 (2005 May).] Their position still holds as of May 2006.
Oral Anti-itch Medications:
- Sedating antihistamines, such as hydroxyzine or diphenhydramine, can be useful adjuncts when taken at bedtime, especially with flares.
- Mast cell stabilizers, such as ketotifen, can be useful when there are other atopic manifestations, such as asthma, rhinitis.
- There may be a secondary infection with S. aureus, even without obvious impetigo, that can lead to a flare.
- Usually topical therapy, such as mupirocin (Bactroban®) or fusidic acid ointment (Fucidin®), is sufficient to help clear the eczema.
- In rare widespread cases, oral cloxacillin or a cephalosporin is required, after swabbing for cultures and sensitivities.
- For very resistant cases systemic treatments such as PUVA, UVB, cyclosporine, azathioprine, or methotrexate can be used. Systemic steroids are sometimes used short-term.