Eczema

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Eczema
Classifications and external resources
Typical, mild dermatitis
ICD-10 L20-L30
ICD-9 692
OMIM 603165
DiseasesDB 4113
MedlinePlus 000853
eMedicine Derm/38  Ped/2567

Eczema is a form of dermatitis, or inflammation of the upper layers of the skin. The term eczema is broadly applied to a range of persistent or recurring skin rashes characterized by redness, skin edema, itching and dryness, with possible crusting, flaking, blistering, cracking, oozing or bleeding. Areas of temporary skin discoloration sometimes characterize healed lesions, though scarring is rare.

Contents

[edit] Types

ICD-10 codes are provided where available.

The term eczema refers to a set of clinical characteristics. Classification of the underlying diseases has been haphazard and unsystematic, with many synonyms used to describe the same condition. A type of eczema may be described by location (e.g. hand eczema), by specific appearance (eczema craquele or discoid), or by possible cause (varicose eczema). Further adding to the confusion, many sources use the term eczema and the term for the most common type of eczema (atopic eczema) interchangeably.

The European Academy of Allergology and Clinical Immunology (EAACI) has published a position paper which simplifies the nomenclature of allergy-related diseases including atopic and allergic contact eczemas (Johansson et al., 2001, Allergy 56:813). Non-allergic eczemas are not affected by this proposal.

The classification below is clustered by incidence frequency.

[edit] More common eczemas

  • Atopic eczema (aka infantile e., flexural e., atopic dermatitis) is thought to be hereditary, and often runs in families whose members also have hay fever and asthma. Itchy rash is particularly noticeable on face and scalp, neck, inside of elbows, behind knees, and buttocks. Experts are urging doctors to be more vigilant in weeding out cases that are in actuality irritant contact dermatitis. It is very common in developed countries, and rising. (L20)
  • Contact dermatitis is of two types: allergic (resulting from a delayed reaction to some allergen, such as poison ivy or nickel), and irritant (resulting from direct reaction to, say, a solvent). Some substances act both as allergen and irritant (e.g. wet cement). Other substances cause a problem after sunlight exposure, bringing on phototoxic dermatitis. About three quarters of cases of contact eczema are of the irritant type, which is the most common occupational skin disease. Contact eczema is curable provided the offending substance can be avoided, and its traces removed from one’s environment. (L23; L24; L56.1; L56.0)
A patch of eczema that has been scratched
Enlarge
A patch of eczema that has been scratched
  • Xerotic eczema (aka asteatotic e., e. craquele or craquelatum, winter itch, pruritus hiemalis) is dry skin that becomes so serious it turns into eczema. It worsens in dry winter weather, and limbs and trunk are most often affected. The itchy, tender skin resembles a dry, cracked, river bed. This disorder is very common among the older population. Ichthyosis is a related disorder. (L85.3; L85.0)
  • Seborrheic dermatitis (aka cradle cap in infants, dandruff) causes dry or greasy scaling of the scalp and eyebrows. Scaly pimples and red patches sometimes appear in various adjacent places. In newborns it causes a thick, yellow crusty scalp rash called cradle cap which seems related to lack of biotin, and is often curable. (L21; L21.0)

[edit] Less common eczemas

  • Dyshidrosis (aka dyshidrotic e., pompholyx, vesicular palmoplantar dermatitis, housewife’s eczema) only occurs on palms, soles, and sides of fingers and toes. Tiny opaque bumps called vesicles, thickening, and cracks are accompanied by itching which gets worse at night. A common type of hand eczema, it worsens in warm weather. (L30.1)
  • Discoid eczema (aka nummular e., exudative e., microbial e.) is characterized by round spots of oozing or dry rash, with clear boundaries, often on lower legs. It is usually worse in winter. Cause is unknown, and the condition tends to come and go. (L30.0)
  • Venous eczema (aka gravitational e., stasis dermatitis, varicose e.) occurs in people with impaired circulation, varicose veins and edema, and is particularly common in the ankle area of people over 50. There is redness, scaling, darkening of the skin and itching. The disorder predisposes to leg ulcers. (I83.1)
  • Dermatitis herpetiformis (aka Duhring’s Disease) causes intensely itchy and typically symmetrical rash on arms, thighs, knees, and back. It is directly related to celiac disease, and can often be put into remission with appropriate diet. (L13.0)
  • Neurodermatitis (aka lichen simplex chronicus, localized scratch dermatitis) is an itchy area of thickened, pigmented eczema patch that results from habitual rubbing and scratching. Usually there is only one spot. Often curable through behavior modification and anti-inflammatory medication. Prurigo nodularis is a related disorder showing multiple lumps. (L28.0; L28.1)
  • Autoeczematization (aka id reaction, autosensitization) is an eczematous reaction to an infection with parasites, fungi, bacteria or viruses. It is completely curable with the clearance of the original infection that caused it. The appearance varies depending on the cause. It always occurs some distance away from the original infection. (L30.2)
  • There are also eczemas overlaid by viral infections (e. herpeticum, e. vaccinatum), and eczemas resulting from underlying disease (e.g. lymphoma). Eczemas originating from ingestion of medications, foods, and chemicals, have not yet been clearly systematized. Other rare eczematous disorders exist in addition to those listed here.

[edit] Diagnosis

Eczema diagnosis is generally based on the appearance of inflamed, itchy skin in eczema sensitive areas such as face, chest and other skin crease areas. For evaluation of the eczema, a scoring system can be used (for example, SCORAD, a scoring system for atopic dermatitis).

Given the many possible reasons for eczema flare ups, a doctor is likely to ascertain a number of other things before making a judgment:

  • An insight to family history
  • Dietary habits
  • Lifestyle habits
  • Allergic tendencies
  • Any prescribed drug intake
  • Any chemical or material exposure at home or workplace

To determine whether an eczema flare is the result of an allergen, a doctor may test the blood for the levels of antibodies and the numbers of certain types of cells. In eczema, the blood may show a raised IgE or an eosinophilia.

The blood can also be sent for a specific test called Radioallergosorbent Test (RAST) or a Paper Radioimmunosorbent Test (PRIST). In the test, blood is mixed separately with many different allergens and the antibody levels measured. High levels of antibodies in the blood signify an allergy to that substance.

Another test for eczema is skin patch testing. The suspected irritant is applied to the skin and held in place with an adhesive patch. Another patch with nothing is also applied as a control. After 24 to 48 hours, the patch is removed. If the skin under the suspect patch is red and swollen, the result is positive and the person is probably allergic to that substance.

Occasionally, the diagnosis may also involve a skin biopsy: removal of a small piece of affected skin for microscopic examination in a pathology laboratory.

Blood tests and biopsies are not always necessary for eczema diagnosis. However, doctors will at times require them if the symptoms are unusual, severe or in order to identify particular triggers.

[edit] Treatment

[edit] Moisturizing

Dermatitis severely dries out the skin, and keeping the affected area moistened can promote healing and retain natural moisture. This is the most important self-care treatment that one can use in atopic eczema.

The use of anything that may dry out the skin should be discontinued and this includes both normal soaps and bubble baths that remove the natural oils from the skin.

The moistening agents are called 'emollients'. The rule to use is: match the thicker ointments to the driest, flakiest skin. Light emollients like Aqueous Cream may dry the skin if it is very flaky and whilst it is the moisturiser traditionally prescribed by some doctors, it is in fact only licensed for use as a soap substitute on washing.

Emollient bath oils should be added to bath water and then suitable agents applied after patting the skin dry. Generally twice daily applications of emollients work best and whilst creams are easy to apply, they are quickly absorbed into the skin, therefore needing frequent re-application. Ointments, with their lesser water content, stay on the skin for longer and so need fewer applications but they must be applied sparingly if to avoid a sticky mess.

Typical emollients are: Oilatum or Balneum bath oils, Aqueous cream for washing with, Diprobase or Doublebase pump-action creams also used for washing and may be later applied directly to the skin. The preferred moisturiser of dermatologists is a mix of liquid and white-soft paraffins. Sebexol, Epaderm ointment and Eucerin lotion or cream may be helpful with itching. Moisturizing gloves can be worn while sleeping.

[edit] Eczema and detergents

The first and primary recommendation is that people suffering from eczema shouldn't use detergents of any kind unless absolutely necessary. The current medical school of thought is that people wash too much and that eczema sufferers should use cleansers only when water is not sufficient to remove dirt from skin.

Another point of view is that detergents are so ubiquitous in modern environments and so persistent in tissues and surfaces, safe soaps are necessary to remove them in order to eliminate the eczema in a percentage of cases. Although most recommendations use the terms "detergents" and "soaps" interchangeably, and tell eczema sufferers to avoid both, detergents and soaps are not the same and are not equally problematic to eczema sufferers. Detergents increase the permeability of skin membranes in a way that soaps and water alone do not. Sodium lauryl sulfate, the most common household detergent, has been shown to amplify the allergenicity of other substances ("increase antigen penetration")[1].

The use of detergents in recent decades has increased dramatically, while the use of soaps began to decline when detergents were invented, and leveled off to a constant around the '60s. Complicating this picture is the recent development of mild plant-based detergents for the natural products sector.

Unfortunately there is no one agreed upon best kind of cleanser for eczema sufferers. Different clinical tests, sponsored by different personal product companies, unsurprisingly tout various brands as the most skin friendly based on specific properties of various products and different underlying assumptions as to what really determines skin friendliness. The terms "hypoallergenic" and "doctor tested" are not regulated (according to Consumer Reports), and no research has been done showing that products labeled "hypoallergenic" are in fact less problematic than any others.

Dermatological recommendations in choosing a soap generally include:

  • Avoid harsh detergents or drying soaps.
  • Choose a soap that has an oil or fat base; a "superfatted" soap is best.
  • Use an unscented soap.
  • Patch test your soap choice, by using it only on a chosen area until you are sure of its results.
  • Use a non-soap based cleanser.

How to use soap when one must

  • Bathe in warm water — not hot.
  • Use soap sparingly.
  • Avoid using washcloths, sponges, or loofahs.
  • Use soap only on areas where it is necessary.
  • Soap up only at the very end of your bath.
  • Use a fragrance free barrier type moisturizer such as vaseline or aquaphor before drying off.
  • Never use any kind of lotion, soap, or fragrance unless your doctor tells you to or it's allergen free
  • Never rub your skin dry, or else your skin's oil/moisture will be on the towel and not your body.

[edit] Itch relief

Antihistamine medication may reduce the itch during a flare up of eczema, and the reduced scratching in turn reduces damage & irritation to the skin (the Itch cycle).

Capsaicin applied to the skin acts as a counter irritant (see Gate control theory of nerve signal transmission). Other agents that act on nerve transmissions, like menthol, also have been found to mitigate the body's itch signals, providing some relief. Recent research suggests Naloxone hydrochloride and dibucaine suppress the itch cycle in atopic-dermatitis model mice as well.

[edit] Corticosteroids

Dermatitis is often treated by doctors with prescribed Glucocorticoid (a corticosteroid steroid) ointments, creams or lotions. For mild-moderate eczema a weak steroid may be used (e.g. Hydrocortisone or Desonide), whilst more severe cases require a higher-potency steroid (e.g. Clobetasol propionate). They are highly effective in most cases, but must be used sparingly to avoid possible side effects, the most significant of which is that their prolonged use can cause the skin to thin and become fragile (atrophy). High strength steroids used over large areas may be significantly absorbed into the body causing bone demineralisation (osteoporosis). Finally by their immunosuppression action they can, if used alone, exacerbate some skin infections (fungal or viral). If using on the face, only a low strength steroid should be used and care must be taken to avoid the eyes.

Hence, a steroid of an appropriate strength to promptly settle an episode of eczema should be sparingly applied. Once the desired response has been achieved, it should be discontinued and not used for long-term prevention.

[edit] Immunomodulators

Topical immunomodulators like pimecrolimus (Elidel® and Douglan®) and tacrolimus (Protopic®) were developed after corticosteroid treatments, effectively suppressing the immune system in the affected area, and appear to yield better results in some populations. The US Food and Drug Administration has issued a public health advisory about the possible risk of lymph node or skin cancer from use of these products, but many professional medical organizations disagree with the FDA's findings:

  • The postulation is that the immune system may help remove some pre-cancerous abnormal cells which is prevented by these drugs. However, any chronic inflammatory condition such as eczema, by the very nature of increased metabolism and cell replication, has a tiny associated risk of cancer (see Bowen's disease).
  • Current practice by UK dermatologists [1] is not to consider this a significant real concern and they are increasingly recommending the use of these new drugs. The dramatic improvement on the condition can significantly improve the quality of life of sufferers (and families kept awake by the distress of affected children). The major debate, in the UK, has been about the cost of such newer treatments and, given only finite NHS resources, when they are most appropriate to use.[2]
  • In addition to cancer risk, there are other potential side effects with this class of drugs. Adverse reactions including severe flushing, photosensitive reactivity and possible drug interaction in patients who consume even small amounts of alcohol.[citation needed]

[edit] Antibiotics

The disruption to the skin's normal barrier protection through dry and cracked skin allows easy entry for bacteria. Scratching by the patient both introduces infection and spreads it from one area to another. Any skin infection further irritates the skin and a rapid detoriation in the condition may ensue; the appropriate antibiotic should be given.

[edit] Psychological effects

Eczema often comes and goes in cycles, meaning that at some times of the year sufferers are able to feel normal, while at other times they will distance themselves from social contact. Sufferers with visible marks generally feel fine (physically) and can act normal, but when it is mentioned they may become withdrawn and self-conscious. Since it is a condition made worse by scratching, a sufferer with highly visible sores aggravated by scratching often feel as if everyone is looking at the marks and that it is self induced. Although scratching does give a sense of release, it is usually a temporary solution and can lead to problems with constant scratching. Sufferers often shy away from scratching in public, but the solution is to scratch in privacy. In cases of children with eczema, visible scars or scratch marks can lead to suspicion of home abuse or self-mutilation, which causes possible peer rejection and may add to a general level of stress.

[edit] Light therapy

Light therapy using ultraviolet light can help. UVA is mostly used but UVB and Narrow Band UVB are also used. Ultraviolet light exposure carries its own risks, particularly later skin cancers. When light therapy alone is found to be ineffective, it is combined with a substance called psoralen. This PUVA (Psoralen + UVA) combination therapy is termed photo-chemotherapy. Psoralens make the skin more sensitive to UV light, allowing lower doses of UVA to be used.

[edit] Diet and Nutrition

Recent studies provide hints that food allergy may trigger atopic dermatitis. For these people, identifying the allergens could allow an avoidance diet, although this approach is still in an experimental stage[2].

[edit] Alternative therapies

Non-convention medical approaches include traditional and new-age approaches. Patients should inform their doctor/allergist/dermatologist if they are pursuing one of these treatment routes.

Historical sources - notably traditional Chinese medicine and Western herbalism - suggest a wide variety of treatments, each of which may vary from individual to individual as to efficacy or harm. Toxicity may be present in some. Some of these remedies are for topical use, some are to be ingested.

Oatmeal in solution applied topically is also an alternative therapy[3].

[edit] Research

Other than direct treatments of the symptoms, no cure is presently known for most types of dermatitis; even cortisone treatments and immunomodulation may often have only minor effects on what may be a complex problem. As the condition is often related to family history of allergies (and thus heredity), it is probable that gene therapy or genetic engineering might help.

Damage from the enzymatic activity of allergens is usually prevented by the body's own protease inhibitors, such as, LEKTI, produced from the gene SPINK5. Mutations in this gene are known to cause Netherton’s syndrome, which is a congenital erythroderma. These patients nearly always develop atopic disease, including hay fever, food allergy, urticaria and asthma. Such evidence supports the hypothesis that skin damage from allergens may be the cause of eczema, and may provide a venue for further treatment[4].

Another study identified a gene that the researchers believe to be the cause of inherited eczema and some related disorders. The gene produces the protein filaggrin, the lack of which causes dry skin[5]

[edit] References

  1. ^ Corazza M, Virgili A. Allergic contact dermatitis from ophthalmic products: can pre-treatment with sodium lauryl sulfate increase patch test sensitivity? Contact Dermatitis 2005; 52(5): 239-41. PMID 15898995
  2. ^ Kanny G. Atopic dermatitis in children and food allergy: combination or causality? Should avoidance diets be initiated? Ann Dermatol Venereol 2005; 132 Spec No 1: 1S90-103. PMID 15984300
  3. ^ Complementary treatment for eczema - Dr. Trisha Macnair, BBC Health.
  4. ^ Walley AJ, Chavanas S, Moffatt MF, Esnouf RM, Ubhi B, Lawrence R, Wong K, Abecasis GR, Jones EY, Harper JI, Hovnanian A, Cookson WO. Gene polymorphism in Netherton and common atopic disease. Nat Genet 2001; 29(2): 175-8. PMID 11544479
  5. ^ Palmer CN et. al.. Common loss-of-function variants of the epidermal barrier protein filaggrin are a major predisposing factor for atopic dermatitis. Nat Genet 2006; 38(4): 441-6. PMID 16550169

[edit] External links

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