As a cancer consultant and aesthetics expert, Dr Fiona McCarthy is an authority on skincare during cancer treatment. She shares her recommended products with us

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When she's not treating patients in her popular aesthetics clinic in London's Belgravia,  you'll find Dr Fiona McCarthy  – a member of the Royal College of Physicians who has almost two decades of medical experience – working as a consultant oncologist for the NHS.

Holding qualifications in both, Dr Fiona's unique dual expertise stems from her own experience when she was studying for a PhD in cancer  and immunology and became pregnant. She found herself with a severe case of  pregnancy-induced melasma  and after researching her condition – and realising the world of skincare could be a total minefield for many – she decided to pursue further training, this time in aesthetics.

"Oncology and aesthetics might sound like a unusual combination but both are very rewarding in different ways. My skincare knowledge has been really helpful with my cancer patients as more than half of chemotherapy, radiotherapy or immunotherapy patients will get some kind of skin, hair or nail reaction," Dr Fiona tells us.

And while skincare routines might seem frivolous to some, during a battle with cancer, Dr Fiona has made her skincare advice a crucial part of her pre-treatment chat with patients.

"When you receive a cancer diagnosis, you go from living a normal life to being whisked away into a world of appointments and scans. Maintaining a simple routine, which may help with the skin side effects of potential treatment, can often help patients regain a sense of control," she comments.

To mark Breast Cancer Awareness Month this October, we asked Dr Fiona to share her expertise from her top pharmacy and drugstore skin products to the best ingredients for soothing a post-chemo complexion.

What are the side effects of cancer treatment on the skin?

There are three main types of cancer treatments – radiotherapy, chemotherapy and the newer immunotherapy. They can impact the skin in their own way, according to Dr Fiona.

"Chemotherapy targets cancer cells which are rapidly dividing. Unfortunately, it can not differentiate between these and other rapidly dividing cells in the body including skin cells – as a result, chemotherapy can have an effect on the skin in many ways and this can have a significant impact on patients' quality of life.

"Radiotherapy uses high doses of radiation to target cancer in a particular area. This can cause very florid skin reactions in some cases, with red, sore and irritated skin being a common side effect.

"Immunotherapy is a treatment that modulates your own immune system to fight against cancer. Skin side effects are very prevalent (mainly in the form of rashes) and these can occur during treatment but also many years into treatment and even after treatment has finished.

"There are also certain types of targeted cancer agents that can cause something called an 'acneiform rash.' This isn't traditional acne  but to an ordinary person, it can look just like acne with painful yellow pimples on the face and body. However this is as a direct result of the cancer agent and can often indicate that the treatment is having an effect on the cancer.

"If you're undergoing radiotherapy or immunotherapy, in particular, and you notice any new skin complaints, rashes or reactions, it's really important to speak to your oncologist. Don't self-diagnose or self medicate as there are often very special things they need to prescribe, along with antibiotics or steroids," explains Dr Fiona.

What skincare and haircare ingredients should I avoid during cancer treatment?

Soap is one of Dr Fiona's no-go ingredients since it's extremely drying; likewise, strong active ingredients. "Many of the ingredients you can usually tolerate, such vitamin C , might burn and sting. I'd be very slow to use retinol  as it already causes dryness and many chemotherapies leave skin extra sun-sensitive," she tells us.

If you're undergoing radiotherapy, specifically, Dr Fiona also advises shunning any body creams or lotions containing petroleum jelly since it creates a false barrier on the skin and can worsen any radiotherapy induced skin reaction.

Don't be in a hurry to get back to using actives either, she cautions. "Even after you've finished your cancer treatment, it can take up to nine months for your skin to go back to normal. When reintroducing actives, use just one at a time for two or three weeks to see how you get on."

And what about haircare? " Sulphates  should be avoided since your scalp can become irritated, especially when you lose your hair. Avoid any synthetic fabrics on your head, opting for cashmere hats instead, and use a lower heat setting on your hairdryer," continues Dr Fiona.

She recommends the charity  Cancer Haircare  which offers tutorials from top hairdressers for patients undergoing or recovering from cancer treatment.

What are the best skincare products to use during cancer treatment?

Cleanse, moisturise and protect: that's Dr Fiona's mantra when it comes to caring for skin during cancer therapy.

She advises all her patients to start their new gentle skincare routine a week before cancer treatment begins. "There is evidence  that a pre-emptive skincare regime can really help the quality of life when it comes to skin side effects of cancer treatment.

"Opt for unfragranced, pH-neutral skincare. Keep showers and baths lukewarm, pat – rather than rub – your skin dry and apply your moisturisers as soon as you finish bathing while your skin is still a little damp," says Dr Fiona.

Here's what's in her toolkit:

The best cleanser during cancer treatment

"For a pH-neutral, non-fragranced, non-soap cleanser, I like Avene Extremely Gentle Cleansing Lotion , £11.50, particularly for taking makeup off. I also like Cerave cleansers, £9.50. They contain niacinamide  and ceramides to help maintain the skin barrier and avoid stripping your skin."

The best shower gel during cancer treatment

"If you're still craving a hint of fragrance, the shower is probably the best place for it, as it can be washed off quickly. But ideally, you want to avoid using any scented products. I recommend the Sanex Shower Gels , £2.29."

The best face moisturiser during cancer treatment

" La Roche-Posay Toleriane Ultra , £18.50, is specifically designed for sensitive skins. Crucially, it contains humectants (to draw water in) and occlusives (to keep it in)."

The best body moisturiser during cancer treatment

"I really rate Aveeno Daily Moisturising Body Lotion , £7.69. It's soothing, unfragranced and contains colloidal oats that have a prebiotic function to help maintain the skin barrier.

If you need extra nourishment, La Roche-Posay Cicaplast B5 Repairing Balm , £14, is thicker and contains pro-vitamin B5 which, again, reduces transepidermal water loss."

The best hand cream during cancer treatment

"Sore, cracked and tingly hands are a common problem. Look for hand creams with a high emollient, urea or glycerin count – they should be in the first two or three ingredients on the back – and apply one every time you wash your hands. O'Keeffe's Working Hands , £8.49, has a really high percentage of glycerin. You need between 10 and 30 per cent to really see an effect. I also like Nursem Caring Hand Cream , £9.99."

The best foot cream during cancer treatment

" Flexitol Heel Balm , £5.09, is my secret weapon. It's a heel balm with a very high count of urea – a humectant, meaning it draws moisture into the skin. I tell my patients to put it all over their feet then pop on a pair of cotton socks before bed."

The best lip balm during cancer treatment

Dr Fiona says “I recommend  La Roche-Posay Cicaplast Lip Balm , £7, that contains panthenol which improves skin hydration as well as having anti-inflammatory effects."

The best sunscreen during cancer treatment

"This is where the 'protect' element comes in. It is essential to protect the sun during cancer treatment. Certain chemotherapy agents in particular are “photo sensitisers” which means they make the skin more sensitive to sunlight and UV rays. Ideally, choose a physical or mineral SPF as these deflect rather than absorb UV rays and form a physical barrier. Examples include  Skinceuticals Mineral Radiance UV Defense SPF50,  £41 or  Heliocare Mineral Tolerance Fluid, £31. "

Useful gifts for cancer patients

One of Dr Fiona's most-asked questions is what to buy someone going through cancer treatment. But while it can be tempting to treat someone to spa-like bath oils and divinely-scented body creams, she advises steering well clear.

"All cancer treatments – including chemotherapy, radiotherapy and immunotherapy –have the potential to leave skin dry, sensitive and red so the last thing you want to do is irritate it further with alcohol, essential oils and fragrance," explains Dr Fiona.

If they like fragrance, she suggests a  scented candle  or a  diffuser  as a more practical alternative.

"Some chemotherapy drugs can make hands and feet more sensitive to the cold and cause extreme tingling. A gift of warm gloves and socks is always a welcome one to combat these symptoms.

"Another sensible gift is to upload some new books or a film onto someone's tablet. Simple distractions, like these, can help to pass the time more pleasantly while they're waiting around during treatment.

"Silk or cotton headscarves and turbans are an excellent choice for patients suffering from sensitive scalps following hair loss. I've also recently come across The Cancer Care Parcel  – an excellent company that puts together hampers based on age, gender and interests. It takes advice from cancer patients on the items they've genuinely found useful during their journey," Dr Fiona adds.

Dr Fiona is offering online skincare consultations, £30 for 30 minutes, or free if you're going through cancer treatment, at  Get Harley  - a digital platform giving you easy access to leading beauty industry practitioners.