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  • Acne is a common disease that affects many people at some time during their lives.

    Acne explained

    Acne is caused by overactive sebaceous (oil) glands at the base of hair follicles. The oil, skin cells and hair in the pore can clump together and form a plug. When the pore becomes blocked, bacteria infects the pore, causing swelling and redness. If the plugged pore is open, it is called a blackhead. The dark colour is due to surface pigment, not dirt. When the pore is covered by skin, it is called a whitehead. Other signs of acne are small red bumps called papules or pus-filled lesions called pustules.

    The face, upper chest and the back – the parts of the body with the greatest number of oil glands – are most affected by acne.

    Acne is classified as mild, moderate or severe, depending on the number of spots or marks on the skin. Acne is mild if there are less than 20 marks, moderate if the count is between 30 and 125 and severe if the count is greater than 125.

    Genetics, hormones and bacteria

    Genetics plays a big role in an individual’s predisposition to acne. Other contributors are hormones, infections, diet and stress.

    During puberty, hormones lead to increased production of sebum (oil). Puberty is also when skin bacteria numbers increase, including Propionibacterium acnes (P. acnes).

    P. acnes bacteria live in follicles and use the oil and dead skin cells as food sources. Blocked follicles allow the bacteria to multiply, and it is this rapid growth that triggers inflammation.

    There are phages (viruses that infect bacteria) naturally found on our skin. Scientists think that people who are not affected by acne may have a sufficient population of phages to keep the P. acnes bacteria in check. People for whom acne is a problem may not have enough phages to prevent the bacteria from aggravating their immune systems. Read about this research in Waging war on acne.


    Treatment for acne usually depends on the person’s age, sex and the length and severity of the acne. Some general self-care treatments that may help are:

    • gently cleansing the skin with a mild soap, twice daily
    • keeping hair clean and away from the face
    • using water-based products rather than oil-based make-up or moisturisers
    • removing make-up at night.

    Non-prescription medications are effective for some people. Topical creams and solutions often have antiseptics to reduce the number of P. acnes bacteria. They also work to unblock hair follicles and calm inflamed skin. Moderate or severe acne may require prescription medications.

    New Zealand companies helping to fight acne

    Hamilton-based biotechnology company Quantec Ltd has created a range of skincare products that use bioactive milk proteins called IDP (immune defence proteins). The bio-proteins have scientifically proven antimicrobial and anti-inflammatory properties that prevent the spread of disease causing bacteria. They also leave the natural and beneficial skin bacteria largely unaffected. Read about the commercialisation and clinical trialling of IDP in Bioactive milk proteins attack acne.

    Douglas Pharmaceuticals is another New Zealand company with a proven acne treatment product. Oratane (isotretinoin) is a prescription medicine that markedly reduces sebum production and shrinks the skin’s sebaceous glands. Read about isotretinoin in the article FDA approval for NZ-made acne treatment.

    Useful links

    DermNet New Zealand has extensive information about acne and other skin concerns.

    Visit the Quantec website to read about the bioactive protein isolate called IDP and its uses in human and animal health applications.

      Published 26 May 2017 Referencing Hub articles
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