Eczema

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Eczema, also known as dermatitis, is a condition characterised by dryness of the skin. One of the range of atopic conditions, indicating an underlying allergic response. Associated with hayfever and asthma. There is some genetic association.

Info bulb.pngEasily described to patients:

Imagine the skin as a wall made of bricks and cement. Normal skin has good cement holding the bricks (the cells) together. People with eczema have faulty cement that makes the bricks unstable. This means that they can't prevent bugs from getting between the bricks and causing irritation. The idea of treating eczema is to restore the cement so that the bricks create a good barrier against infection and irritation again.

Contents

Treatment

The mainstay of treatment in eczema is complete emollient therapy, combining

  • Emollient put on as often as possible
  • Soap substitute
  • Bath emollient

This should prevent soaps and water from stripping skin of the natural oils, and should increase the ability of the skin to act as a barrier to infection. After bathing, in a short bath with water that is not too hot, patients should pat themselves dry, because heat and vigorous rubbing has the potential to stimulate a histamine release from Mast cells and cause itch. While still damp, a thick layer of emollient should be applied and allowed to soak in. Emollient should be put on as often as possible. It is a good tip for babies with eczema, that they be moisturised whenever they have a nappy change.

The amount of emollient prescribed is vital. 30g is enough for a single application of a cream to the entire body of a 70kg average adult. Therefore in an adult with marked eczema to be using the right volume of emollient you would expect use of 500g a week. In children or babies 500g every 2-3 weeks should suffice. Ideally patients should have a choice in the type of emollient they like - many prefer those in pump dispensers - which are ideal as it retains some sterility of the product. Greasier creams are less likely to be used - they are less well tolerated because of the greasiness - leaving a trail is inconvenient. However, they are more effective.

LogoKeyPointsBox.pngAn adult with marked eczema should be using 500g of emollient a week

Eczema Flare

This usually occurs due to a lack of consistent emollient use or contact with a specific allergen or bacterial antigen. See eczema flare

Topical Steroids

When eczema worsens it is often necessary to use topical steroid creams.

  • The least potent cream that is sufficient to treat the problem is the best.
  • Steroids should be used sparingly and for short periods.

Steroids should be applied according to the FTU rule (described by CC Long and AY Finlay in 1991).[1] One fingertip unit (the distance between the tip of the finger to the crease of the DIP joint) should cover the equivalent of area of two palmar surfaces on the patient's body. One FTU in an adult is approx 0.5g. So from this you can calculate how much cream will be required per week for a patient using the correct amount of steroid.

Dose of cream in a fingertip unit varies with age:

  • Adult male: one fingertip unit provides 0.5 g
  • Adult female: one fingertip unit provides 0.4 g
  • Children of four years ­ approximately 1/3 of adult amount
   * Infants six months to one year­ approximately 1/4 of adult amount

Amount of cream used varies with body part:

   * One hand: apply one fingertip unit
   * One arm: apply three fingertip units
   * One foot: apply two fingertip units
   * One leg: apply six fingertip units
   * Face and neck: apply 2.5 fingertip units
   * Trunk, front & back: 14 fingertip units
   * Entire body: about 40 units

Other Treatments

New immunomodulatory drugs are helpful but current advice is they should be prescribed only by doctors with an interest in Dermatology. They can be very helpful especially in childhood eczema, but the cost may be prohibitive.

Eczema flare may also occur due to superantigens from infection with Staphylococcus aureus. This is a normal skin commensal but, using the "brick wall" analogy, the antigens can irritate more significantly in eczematous patients. In those who do not seem to settle with conventional steroid treatment, or those with associated systemic features of fever or malaise, then an antibiotic is useful. Oral antibiotics are helpful in widespread cases. Topical antibiotic or antibiotic/steroid preparations can be very useful, BUT should not be used for longer than 2 weeks because this risks selecting resistant organisms and spreading antibiotic resistance. A severe flare may also benefit from the use of a Chlorhexidine type soap to try to clear commensal skin flora and possibly nasal clearance of Staph too. Several bath emolients contain anti-staphylococcal disinfectant and are intended to have the same effect.

Dressings

Weeping eczema may require dressing to assist healing, ichthopaste bandaging is helpful in very inflamed cases but needs to be taught to patients by someone experienced in the subject. Wet wrapping is a very useful tool for itchy children who have problems with nocturnal itch that affect their sleep. Wet wrapping involves the use of bandages (there are prescribable ones such as Tubifast and Tubifast garments). Emollient and/or steroid is applied to the affect area. Bandages or garments are soaked in cool water, wrung out and applied over the cream. A second dry layer is applied over the top. This not only reduces drying overnight, it encourages absorption of the treatment creams and reduces the risk of excoriation overnight.

Treatment for Itch

Extreme itch may respond well to sedating antihistamines, like Hydroxyzine, taken in the evening.

Eczema complications

Dennie-Morgan Fold 
A darkened fold of skin under both eyes associated with atopic eczema
Eczema Herpeticum 
A superinfection of eczematous skin with Herpes Simplex Virus often causing rapid deterioration of the patient and requiring hospital admission.
Lichenification 
Where repeatedly excoriated tissues become thickened with exaggerated skin markings. These usually require higher potency steroids.
Pompholyx 
An vesicular eczematous eruption, generally on thickened skin such as hands and feet - often described as being like frog-spawn and is sometimes more obvious on palpation than by sight. Tends to be intensely itchy and responds well to moderately potent steroids. In the context of current Tinea Pedis, it is described as an "Id Reaction" (pronounced i-de) but does not represent fungal infection in the hand
Steroid induced acne 
Patients who have eczema often have dry facial skin too. Some may be tempted to apply potent steroids to their faces. This invariably causes telangiectasia and papular eruptions similar to Rosacea. The only treatment is withdrawl of the steroid which will initially cause a flare of the skin and then will slowly regress.
Striae 
If highly potent steroids are used indiscriminately skin thinning and striae can occur.

References

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