The diagnosis of acne is usually straightforward and can be made by examination of the skin, however there are several other conditions that can be confused with acne:-

• Perioral dermatitis: This is a common condition that causes clusters of reddish spots on the chin, around the nostrils and sometimes around the eyes.
• Papular rosacea: This is another common condition causing redness of the face. Some forms of rosacea cause predominantly red spots on the face that can be mistaken for inflammatory acne.
• Milia: These appear as small white spots on the face - particularly on the upper cheeks. They can be mistaken for acne whiteheads. They are caused by the build up of keratin beneath the skin surface.
• Pseudofolliculitis Barbae 'Razor bumps': This condition causes inflamed spots in the beard area. It is thought to result from short hairs irritating the skin and is far more common in men, particularly those with darker skin types.

The treatment is different for these conditions and during an acne consultation, I will examine your skin to verify that the diagnosis of acne is correct and to assess whether co-existing conditions are also present.

Whiteheads, also known as closed comedones, are formed when the neck of the hair follicle becomes blocked, manifesting as a whitish bump on the skin. Blackheads or open comedones are similar in nature, but the opening of the hair follicle is clogged with debris, giving it a black appearance. Inflammatory acne, the classic acne spot, presents as a red lesion and occurs when the hair follicle becomes inflamed or infected. Further inflammation or infection can lead to pustules, which are collections of white blood cells and acne nodules and cysts, which are large lumps that may persist for extended periods and have the potential to cause significant scarring.

During your consultation I will establish the types of acne lesions that you have, the degree of severity of your acne and I will look for features of hormonal acne which often affects the lower face and jaw and can vary in severity with the hormonal cycle.

A number of factors can trigger worsening of acne and I will ask you questions to assess whether any of the following could be relevant:-

• Hormonal factors: The production of sebum is increased by hormonal changes that occur at puberty and this is an important factor in the development of acne. Most patients with acne do not have a hormonal abnormality, however if there are other factors such as irregular periods and/or excessive hair growth the diagnosis of polycystic ovary syndrome (PCOS) should be considered.
• A change in hormonal contraception, for example stopping the combined oral contraceptive pill, changing to a new brand or starting progesterone only contraception 'minipill' can trigger a flare of acne.
• Medications: Certain medications including oral or topical steroids and some cancer treatments can trigger the development of acne so it is important to tell me about all medications that you are using.
• Thick or greasy moisturisers or make up can block the opening of the hair follicle triggering the development of acne.
• Beard oils, waxes and greasy skin and haircare products.
• Sweating: This can make acne worse, particularly on the back.
• Pressure, for example from a motorcycle helmet or from a weight bench in the gym can compress the openings of hair follicles triggering acne.
• Diet: In most cases, diet does not play a significant role in the development of acne however some studies have shown an association between a diet high in milk or high glycaemic index foods.

There are several things that you can do to minimize breakouts on the back:

• Wash with dermol 500 rather than soap or shower gel Use benzoyl peroxide
• Wear light cotton clothing next to the skin rather than tight compression garments
• Try to minimize pressure on the back - for example from benches in the gym

Despite these measures it can be difficult to treat acne on the back with topical products (creams/ointments/lotions) since it is hard to access and it is a large area and some patients will need tablet treatments such as oral antibiotics or isotretinoin.

Scarring reflects the body's natural response to injury. Whilst wounds in the human fetus can heal with no scar, all healing after birth is associated with at least some degree of scar formation.

As for any cause of severe inflammation, acne lesions cause damage to the epidermis and the dermis with death of keratinocytes and fibroblasts and damage to normal skin structures such as hair follicles and sweat glands. This damage is repaired by growth and division of fibroblasts - the cells responsible for production of the connective tissue in the skin. This leads to the formation of tough bands of connective tissue that characterize scar tissue and can be contrasted with the delicate fibres that make up the normal dermis.

After acne has been controlled scars will often improve significantly in appearance over time due to the natural remodeling of collagen that occurs with skin healing. For this reason it is usually advisable to wait for a minimum of 6 months and usually a year after completing treatment of acne before performing invasive procedures for treatment of acne scars. Another reason to delay treatment is that Isotretinoin can impair wound healing and increase the risk of poor healing.

Like retinoids, retinol causes skin cells to divide and shed reducing blockage of hair follicle openings (pores). Retinol is also thought to have numerous other benefits for the skin including improving pigmentary abnormalities and can improve the appearance of fine lines and wrinkles.

Retinol is milder than prescription-strength retinoids and can be incorporated into your daily skincare regimen. It is generally well tolerated but can cause skin irritation and dryness. If you suffer from this try a milder retinol preparation such as SkinCeuticals 0.3% retinol. Retinol can also make you more sensitive to the sunlight so it is important that you use a sun block.

5% benzoyl peroxide is available in gel and face-wash formulations without prescription and is present at lower concentrations as an ‘active’ ingredient in a number over the counter products such as cleansers. It is additionally included with other prescription-only topical treatments such as retinoids (e.g. epiduo) or antibiotics (e.g. duac).

Benzoyl peroxide can be an effective treatment for mild acne, however it takes several weeks until you start seeing the effects. On its own It is not a suitable treatment for moderate or severe acne.

Benzoyl peroxide is a safe treatment, that is usually well tolerated, however it can irritate the skin - particularly if used in large quantities. It can also make your skin more sensitive to sunlight and can bleach clothes and hair.

Antibiotics can be used topically (directly on the skin as creams, gels or ointments). Antibiotics used in this way include erythromycin (for example Zineryt) and clindamycin (for example duac gel or dalacin T).

Antibiotic tablets will usually be taken for a course of a few months of treatment. The most common are tetracyclines, for example, lymecycline are usually well tolerated. Other antibiotics that can be used include erythromycin or trimethoprim. Antibiotic tablets can be very effective treatments for mild or moderate acne, however acne can recur when they are discontinued.

There are multiple combination products available. Where needed Dr Lynch can also prescribe custom combination treatments for acne.

The combined oral contraceptive pill (OCP) can be an effective treatment for women. Forms of the OCP, such as Yasmin, that also block male hormones (androgens) are particularly effective. All forms of contraceptive pill require ongoing monitoring and for this reason are prescribed by your general practitioner rather than a dermatologist.

Spironolactone is another option for women. It works by blocking male hormones and reducing sebum production. It is essential that you do not become pregnant whilst taking this treatment and it must be used with effective contraception. Other potential side effects include breast tenderness and high blood potassium - the latter requires blood tests for monitoring.

Pigment in the skin is produced by a specialized population of cells known as melanocytes. These are situated between the thin surface layer of the skin (the epidermis) and the thicker, deeper layer that give the skin its strength (the dermis). Inflammation occurring in acne can cause melanocytes to produce additional pigment, additionally inflammation causes death of melanocytes and as a consequence they fall deeper within the skin where they are engulfed by immune cells.

Whilst these dark marks will fade with time, they can persist for many months after acne lesion have resolved and for some patients can be a greater concern than the acne lesions themselves. Assiduous photoprotection is critical; skin products including hydroquinone and retinoids and cosmeceuticals may give some minor improvement, however the most important factor is to find an effective treatment to prevent the development of further acne.

It is always advisable to use a sun block daily to prevent skin cancer, post-inflammatory hyperpigmentation and premature skin aging. I like products from the Heliocare 360 and Anthelios XL ranges.

Acne conglobata can lead to severe scarring over the counter treatments and topical treatments on their own are ineffective and it will usually require a powerful oral medication such as isotretinoin prescibed by a dermatologist to get control. In some cases steroid tablets (prednisolone) may be used in conjunction with isotretinoin to reduce inflammation.