Friday, March 19, 2010

Sensitive (S) or resistant (R) skin type - acne-prone skin

The next category in our skin type parade is the sensitive vs. resistant type of skin. This skin type is in addition to your oily vs. dry type - so you can be, like me, OS or oily sensitive!

Resistant skin has a great stratum corneum that provides protection to your skin, keeping out the irritants and allergens. You are unlikely to see redness on your skin, unless you have a sunburn, or acne (although you can have hormonal fluctuations that might cause a few pimples here and there). On the positive side, you can use pretty much any product you want. On the down side, this means some products may be ineffectual for your skin if it needs to penetrate the stratum corneum (like AHA or salicylic acid or propylene glycol), as you have a high threshold for skin penetration.

Is it wrong that I envy resistant skinned people so much I'm making my frowny face - which is not easy when your forehead is filled to the rim with the rich taste of therapeutic Botox!

Sensitive skin comes in four categories - acne type, rosacea type, stinging type, and allergic type. You may have more than one type of sensitive skin, or one type on your face and another on your body. They are characterized generally by inflammation, so the first goal for treating sensitive skin is to reduce inflammation - and we can do this in many different ways with lovely phytosterols in our oils and butters, polyphenols in our oils and extracts, and through other ingredients we can add.

This skin type is generally found in the 11 to 25 year age range, but we can suffer from acne through hormonal fluctuations throughout our lives. It is characterized by being prone to acne, blackheads, and whiteheads. There are four main features of acne prone skin...
  • an increase in sebum production;
  • the clogging of pores from dead keratinocytes inside the hair follicles that cling more strongly than those in non-acne prone type skin;
  • the presence of Propionibacterium acnes (P. acnes);
  • inflammation.
Increased sebum production is obvious, but what about this pore clogging problem? We know about desquamation - when our skin cells shed - but how does this affect acne type skin?

Normally the keratinocytes shed off and reveal new, lovely skin cells. In the case of acne prone skin, the keratinocytes are told to shed, but do not budge. They adhere to our skin and amass in our hair follicles. The P. acnes bacteria migrates into the hair follicle, where the combination of bacteria, sebum, and dead keratinocytes stimulate the release of cytokines and other inflammatory factors. Our own immune system creates the inflammation and pus that we find in a pimple!

We can treat acne prone skin the same way we treat oily skin - we can't reduce the sebum significantly with anything other than oral retinoids, but we can use mild cleansers to remove some of the oil and use light exfoliation to help remove some of those stubborn keratinocytes. We can do this chemically - with salicylic acid or white willow bark - or mechanically - with a washcloth, very gentle brush, or jojoba or clay beads. We can also use astringent ingredients to make our skin feel a less oily.

Reducing inflammation is easier than it sounds! We can use phytosterols in oils to help - but wait, we shouldn't be using oils on oily, acne prone skin, so we turn to our water soluble extracts and hydrosols.

Most, if not all, of the hydrosols I've reviewed are good for acne prone skin - you want something that offers great inflammation reduction as well as astringency. I especially like chamomile, clary sage, honeysuckle, lavender, orange (neroli), and rosemary hydrosols.

When choosing an extract, try to find something that is both anti-inflammatory and astringent. If it offers anti-bacterial properties, then you've got a triple threat!
  • White willow bark is anti-inflammatory and analgesic, and contains salicylic acid. (Here's a link to a foaming facial cleanser containing white willow bark extract.)
  • Comfrey root is anti-inflammatory, anti-bacterial, and astringent.
  • Chamomile is anti-inflammatory, anti-irritating, exfoliating, and astringent. It also reduces TEWL for up to 48 hours!
  • Honeysuckle is anti-inflammatory, anti-bacterial, anti-irritating, and exfoliating. This would be my first choice for acne prone skin!
  • Cucumber is anti-inflammatory, moisturizing, analgesic, and astringent.
  • Rosemary is anti-inflammatory, moisturizing, astringent, and anti-bacterial.
  • Green tea is anti-inflammatory, slightly astringent, and anti-bacterial.
Aloe vera is a great addition for acne prone skin. It's a good anti-bacterial and anti-inflammatory ingredient that will soothe and moisturize inflamed skin. And don't forget about allantoin - it's a good barrier ingredient that acts as an anti-inflammatory and astringent ingredient.

When you are formulating mineral make-up for acne prone skin, you want to do all the good things you'd do for oily skin, but try to include an extract or two that offers anti-inflammatory and anti-bacterial features. Try adding a little honeysuckle or cucumber extract to your powders at 0.5%, and remember allantoin is your friend!

What if your acne is hormonal but you really have dry skin? Ah, there's a problem. We don't want to put oils on acne prone skin, but we need to keep dry skin hydrated, so how do we do that? We can do that with lots of humectants, extracts, and everything else I've mentioned above. If you can handle a little oil when you've got a break-out, then add one of these things to your moisturizer and wait until the pimples subside. If you can't handle oil, then try using a toner with less astringent extracts (honeysuckle is great, cucumber less great) and don't moisturize the broken out area with an oil in water lotion.

Join me tomorrow for another sensitive skin type - rosacea type!


pearlyn said...

hi ger.

figured u too busy to reply my email.

i decided to add both Cetrimonium Bromide & Cetrimonium Chloride into my leave in hair conditioner how many percent of each do i add?

can Trimethylsilylamodimethicone replace silicone to be added into the formula? if so, how much to add in? it says recommended rate is 0.5 to 2% though..


Susan Barclay-Nichols said...

I've commented on your question in the post on cetrimonium bromide to keep things more organized.

Cushla Grace said...

I have been reading your posts on skin types, and puzzling over my friend's comment when I asked her about her skin. She said: "My skin is really sensitive and dry, but yeah heavier creams tend to send my skin into grease overdrive.... What would you suggest to use in a lotion? The drier oils? Many thanks, I love your blog. Kirsten from NZ

Alexis said...

Hi Cushla Grace,
I hope you and Susan don't mind me weighing in here, but I would like to respond to your question, as I have the same problems as your friend. I am chemically sensitive, and I used to be so oily that I could not tolerate any oils on my skin. As I've aged my skin is much drier, but still super sensitive. I can use some drier oils and almost all the esters, but absolutely no silicones (too occlusive). To formulate for her, have her patch test a couple of oils, neat, on her jaw. If she doesn't react use those to formulate a lotion. Susan also has some great recipes for "oil-free" lotions that will give your friend the moisture she needs without too much occlusion.
Good luck!

Cushla Grace said...

Thank you that's such a good suggestion about the test patches. This has given me more to think about, I appreciate it.

Lu said...

Hi, Susan! I was hoping you had some info on using squalane on oily, sensitive, acne prone skin?

Susan Barclay-Nichols said...

Hi Lu! Have you read the posts I've written about squalane? Loads of information in there!