Vicious Circle of Atopic Eczema

Atopic eczema all starts with the itch, which then gets driven by toxins produced by Staph. aureus once there is broken skin and continuous scratching and re-breaking of skin.

1. Itchy, dry skin
2. Scratching breaks the skin surface.
3. Lesions begin to weep.
4. Staphylococcus aureus (Staph. aureus) infect skin and colonise weeping lesions.
5. Toxins that are released by the Staph. aureus stimulate the body’s natural immune response.
6. The person’s mast cells release histamine. Mast cells are the tissue cells of our immune system – refer to Britannica Encyclopedia or Wikipedia. Immune system proteins called antibodies, which are bound to mast cells, bind to foreign substances/antigens (in this case, the Staph. aureus toxins) to remove them, but in the process the mast cells are stimulated to release their histamines.
7. Histamine causes inflammation and itch.

And then we have itchy, dry skin again….and the circle continues until we stop it by ensuring there is no more breaking of skin…

Source: a photo we took of the educational material that was shown to us during one of our consults by the Eczema Nurse of the Paediatric Community Nursing Team, Child Health Service, Wellington Hospital, Capital & Coast District Health Board.

Signs of Staph. Aureus skin infection

How do you spot that skin is being or is already infected by Staph. aureus bacteria?

Red spots on the skin – yes, it’s that simple and very easy to overlook. Look closely at the image on the right showing three separate stages of Staph. aureus bacteria on the skin and the equivalent in a petri dish!

Source: a photo we took of the educational material that was shown to us during one of our consults by the Eczema Nurse of the Paediatric Community Nursing Team, Child Health Service, Wellington Hospital, Capital & Coast District Health Board. Click here to download a PDF version of the Signs of Skin Infection photo (339kb).

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Here are some other photo examples of skin infection in various stages:

1. (Above) Staph. skin infection that’s already past the initial red spotty stage and starting to spread. Notice how it can also form a “ring” around the actual eczema patch. It’s best to start the antibacterial treatment even before it hits this stage.

2. (Above) Staph. skin infection that is even further along. The bacteria is flaring up into raised pimple -like lumps.

3. (Above) The Staph. skin infection is now looking more like what I would have usually thought to be “early infection” – but actually, the bacteria are well into their game now! You can notice the wet and dried up dark yellowy pus – signs that the body’s white blood cells are really trying to fight the bacterial infection. Urgent / intensive antibacterial treatment is needed to stop this infection from getting worse!

Bacteria you should know about: Staph. aureus

Quoted snippets from DermNet NZ http://dermnetnz.org/bacterial/staphylococci.html:

Staphylococci (‘staph’) are a common type of bacteria that live on the skin and mucous membranes (eg. in nose) of humans. Staphylococcus aureus (S. aureus) is the most important of these bacteria in human diseases.

About 15-40 per cent of healthy humans are carriers of S. aureus, that is, they have the bacteria on their skin without any active infection or disease (colonisation). The carrier sites are usually the nostrils and fexures, where the bacteria may be found intermittently or every time they are looked for.

Despite being harmless in most individuals, S. aureus is capable of causing various infections of the skin and other organs. S. aureus infections are common in people with frequent skin injury, particularly if the skin is dry.

They are generally very hardy organisms.

They are only able to invade via broken skin or mucous membranes, hence intact skin is an excellent human defence. Once they have invaded they have various ways to avoid host defences. They:

• Hide their antigens to avoid an immune response
• Kill infection-fighting cells (phagocytes)
• Survive within host infection-fighting cells.
• Develop resistance to antibiotics
• Release toxins (intoxication) – these do not require the presence of live bacteria to have an effect.