Monday, 22 July 2019 10:26

Understanding Reactive Skin: Contact Irritation, Barrier Impairment, and Sensitization

Written by   Robert P. Manzo

In general, clients and some professionals do not understand the difference between sensitive skin and skin sensitization. These are important concepts to understand for skin professionals.


This article will address this topic with an emphasis on defining the conditions and discussing applications of those definitions for treatable conditions. It is a bit technical, but it is important to understand the differences in skin reactions from a basic clinical approach to be able to resolve skin conditions effectively.



What are the primary complaints described by clients when they report sensitive skin?

  • Red skin (intermittent or chronic)
  • Stinging when anything is applied
  • Burning sensations
  • Skin that heats up unexpectedly
  • Pain when the skin surface is touched or even not touched

To a practicing clinical researcher, these symptoms sound quite familiar and are grouped into specific types of skin reactions. Clinical evaluation tests are performed regularly to determine what types of sensitization is occurring in the skin.


Let’s start with some basics. Skin can be inflamed and sensitive when coming in contact with an irritant of some type. When this irritant comes in contact with the skin, a reaction occurs which sets off a cascade of biochemicals that repair or reduce the inflammation. This can be known as contact dermatitis.


Skin can also become inflamed and sensitive when it is exposed to an irritant over and over again. The skin may not react the first time but may react the second time or the 100th time, depending on the person. The key difference between the contact type of irritation and this sensitization reaction is that this reaction involves the immune system recognizing that this irritant is not compatible with the skin after several uses. A skin irritant can be any material that comes in contact with skin, including many skin care products – this is skin sensitization.


Skin sensitization is the process by which skin can develop increased allergic responses to a substance over time through repeated exposure. Due to immune response, the reaction becomes worse with repeated exposure and it is usually specific to individuals.



A clinical skin test called a Human Repeat Insult Patch Test (HRIPT) can determine the potential for the skin to react in this way. It is a long test and done in phases to understand the specific types of allergic responses that the skin generates.


The Cumulative Irritation Test (CIT) is a different test measure of irritation response to a specific product. Patches of the product are applied to the skin and are then replaced daily throughout the course of the trial to assess response.


There are many tests that can quite precisely measure skin contact reactions, allergic reactions, and many other types of reactions in the skin. These specific types, in a broad sense, give rise to common symptoms as discussed earlier: contact irritation and sensitization.



One of the most common challenges experienced by clients who seek professional help is something that they may not be aware of: barrier function impairment. For a professional, it is critical to recognize. The five primary complaints that people have when seeking help from a provider were discussed. Barrier function impairment should be close to the first root cause looked at in the cases. The diagram shows generally what barrier function impairment is.

Manzo Diagram 1

The stratum corneum or top layer of the skin loses its ability to hold the integrity of its structure. The lipids and surface cells (stratum corneum) come apart and let toxins in and high levels of water out. The property that is measured by clinicians is called transepidermal water loss (TEWL). When the skin is in this state, it immediately starts to exhibit one or more of the symptoms mentioned previously. Some professionals will try to apply redness reduction serums or creams or anti-itching products or pain relievers, but this may actually make the problem worse.


What should a professional do when barrier impairment is suspected? Treat it – not the secondary symptom. How? Remember the barrier impairment diagram. The corneocytes and the lipids must reform that critical structure.


Take a comprehensive history trying to assess what was giving rise to the inflammation issue by applying what was learned in this article previously.


Baseline the skin. This means stop all products being used and only use a sensitive skin cleanser and lotion. If they are high-quality cleansers and lotions, they will be formulated properly and contain anti-inflammatories. The skin will normalize within a week and the barrier should begin to return to normal.


Apply a barrier repair serum to the skin to start the production of lipids and strengthen the corneocyte matrix and underlying keratinocytes. Barrier serums should not be an occlusive product but, rather, a product which incorporates specific bio-peptides to start the skin to produce necessary lipids for the barrier repair process to start.


Maintain this regimen for three months without facials or any other interventions to allow the barrier to fully strengthen and heal.


This process requires discipline by both the professional and the client. It is a process by which a client can experience long-lasting results, but it takes a reliable consultation and interpretation of the skin and the phased process of improvement that is described. Once this process is completed, the professional can move on to corrective therapies without the risk of major side effects from sensitization reactions.



One of the largest groups of clients that needs careful consideration is the acne client. The amount of misinformation in the market is incredible. Let’s start with the basics of acne. It is an inflammatory disease, so if the client is doing anything to inflame the skin, it is probably not a good thing.


As a note, in general, due to the nature of acne as an inflammatory disease, try to avoid microdermabrasion of any type, microneedling, tools which are used to apply pressure to the skin, and devices that scrape or vacuum the skin surface. If an aesthetician is good at their craft, all they need is their hands and technique. Certain types of intense pulse light (IPL) devices and lasers work well for acne – some do not. LED therapy is fine, since it is a non-contact therapy, but its efficacy is still being studied in real life examples of clients.


What is the biggest mistake a skin professional can make when using acne topicals to treat a client? Not considering barrier function impairment as a root cause.


Far too many professionals immediately start to use either one or a combination of:

  • retinoids
  • benzoyl peroxide
  • salicylic acid (beta hydroxy acids)
  • glycolic acid (alpha hydroxy acids)

If a client comes to the spa and is presenting with skin that is red, stinging, burning, has some pain, or all of these symptoms, but is in the middle of a severe breakout, do not apply more product to remedy the situation. Their barrier function is probably severely impaired and adding product will make it far worse. Move into the baselining phase of treatment to try to assess the root cause.


Acne is particularly difficult to treat due its constantly changing nature. A professional may think they have it managed, but then conditions change in a client’s environment and they all of a sudden have a breakout.


The underlying root causes of acne can be:

  • too much or wrong type of oil or sebum
  • hyperkeratotic skin
  • too much or wrong type of bacterial presence
  • hormone imbalance
  • inflammation
  • skin pH

Most of the time, when a client comes to a professional for help with acne, they have tried all the over-the-counter solutions, infomercial products, MLM products, and remedies suggested by friends or influencer videos.


By the time the professional sees them, they are in the cycle of skin sensitivity or sensitization reactions or general contact dermatitis. If the professional tries to treat them by adding more active ingredients (even a simple green tea solution), it can break them out more. This is the most common mistake made by professionals. Even the addition of Metrogel or other drugs that are applied on the skin can produce problems. Oral antibiotics and other oral drugs will not have this problem.


One of the root causes of acne is dehydration. Most professionals know this, but always super hydrate the skin with a combination of hyaluronic acid and glycerin, along with dimethicone. It will work wonders in reducing sensitive skin reactions, as well as increasing the health of skin overall. Drinking lots of water is important for overall health, and everyone should do it, but drinking a lot of water does not necessarily mean skin will be hydrated, so make sure to hydrate externally as well as internally.


Go into a baselining approach. Let the skin calm down to a point where a professional judgment can be made on what is the actual root cause of the inflammation, rather than just treating another symptom of a previous attempt to fix their skin.


Sensitive skin, skin sensitivity, and acne are all highly related issues, so keep this in mind when doing your best to treat it.



The last challenge to discuss is the improvement of aging skin and the role of recognizing the same issues that are involved with these. The first part of this discussion is ultraviolet protection. It is important to recognize the fact that sun damage on skin can penetrate from the surface though the deep layers of the skin. This damage is initiated by free radicals from the sun and these free radicals will damage all types of tissue – from lipids in the surface of the skin, to live skin cells (DNA), to deep collagen and elastic in the skin.


The free radicals can generate skin sensitivities and inflammation reactions as simple as sunburn, but more complex as a recurring histamine reaction. Make sure clients are using a broad-spectrum sunscreen at a minimum of SPF 30 and are re-applying every two hours if they are in a direct sun environment. Professionals should be providing antioxidants with ingredients such as coenzyme Q10, vitamin C (in its acid state), vitamin E (be careful, as vitamin E can cause a histamine reaction in some people), and some more exotic antioxidants, such as super oxide dismutase (SOD).


This same approach can be applied to antiaging practices in dealing with optimizing skin conditions like improving wrinkles, tone, texture, pore size, sagging, and others. Skin sensitivity and underlying sensitization reactions can cause chronic, low-level inflammation and edema in skin. If a professional is trying to treat aging conditions in skin, this can have a limiting effect on those treatments. When skin is inflamed (particularly chronically) it cannot respond well to improvement techniques like adding peptides to start new cellular activity, microneedling, laser techniques, or even surgical techniques. Always be aware that the reduction of inflammation, skin sensitization, and skin sensitivity is one of the most important things a professional can do for skin over the client’s lifetime.


It is important to note that, although every professional has their favorite techniques and products to use based on experience, every client’s skin is unique, and the same process will not work for everyone. Change the process according to the individual. Understand their skin history, interpret what is observed, measure, and treat uniquely. This is the essence of skin care personalization, but it starts with knowledge, continual training, and practice.


Robert ManzoRobert P. Manzo is the president and chief formulation chemist of Skinprint. He founded Skinprint in 2002 as a cosmeceutical company focused on personalized skin care solutions for providers. Manzo holds 15 patents in skin care and associated fields, including a patent on customized skin care processes. He continues to speak and train medical-based skin care audiences internationally and publishes in trade journals and periodicals regularly.

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