A Dermatologist Guide To A Dry, Flaky Scalp
An Interview with Dermatologist, Dr. Mara Evangelista-Huber
What are some underlying conditions leading to a dry or flaky scalp?
A dry, flaky scalp may be caused by the following:
1. Skin conditions
- Contact dermatitis (e.g. allergy or irritation to ingredients in products applied to the scalp)
- Seborrheic dermatitis
- Psoriasis
- Superficial fungal infections (e.g. tinea capitis)
- Xerosis (dry skin) brought by older age
- Scalp sensitivity
2. Environmental agents
- Ultraviolet radiation
- Extremes of temperature
- Weather/humidity
- Water properties (e.g. chlorine)
- Pollution
3. Stress (physical or emotional)
4. Hair care practices and treatments
Scalp sensitivity is often overlooked in my clinical practice. Symptoms include itching, flaking, burning, tingling, and tightness. A sensitive scalp can be too oily or too dry, and sometimes redness may be present. Although more research is needed, evidence suggests that an impaired skin barrier function and increased water loss may contribute to sensitive scalp. Other skin conditions like atopic dermatitis, psoriasis, and hair loss may also be a factor. I've seen sensitive scalp in those with a history of atopy.
Are there any specific ingredients or products that you would recommend for a dry, irritated scalp?
The management of a dry, flaky, and irritated scalp depends on its underlying cause. If an underlying skin condition, such as atopic dermatitis, contact dermatitis, psoriasis, or seborrheic dermatitis, is causing the dryness, flakiness, and irritation, then it must be addressed first using standard care methods, such as anti-inflammatory agents like steroids or anti-fungals. It's always helpful to see a board-certified dermatologist, as they are experts in both skin and hair care.
Cosmetic hair care products can play a role in treating scalp conditions, either as an add-on to prescription products during a flare-up (such as using a mild shampoo alternated with a steroid or anti-fungal shampoo), or as maintenance between flare-ups to keep the skin barrier healthy.
Are there any ingredients or routine practices to avoid if experiencing Seborrheic dermatitis or flaky, dry scalp?
Let's briefly discuss the common ingredients found in shampoos. Shampoos typically contain a combination of surfactants (cleansing agents), conditioning agents, and other active ingredients that address specific concerns, such as anti-fungal, anti-dandruff, or anti-inflammatory properties.
Studies have shown that certain surfactants, such as anionic sulfates (e.g., sodium lauryl sulfate (SLS) or sodium laureth sulfate (SLES)) and sulfonates (e.g., olefin sulfonate), have a higher potential to cause skin irritation.
Should those with a dry, itchy, irritated scalp go sulfate-free?
Although sulfates, particularly SLS, have the potential to cause irritant reactions, most people tolerate them without issue. The likelihood of irritation varies depending on factors such as the concentration of sulfates, the method of application, environmental conditions like temperature and humidity, the user's skin barrier condition, and the formulation of the product.
- In some studies, less than 0.1% SLS caused irritation, while others showed little irritation to concentrations greater than 20%.
- In many studies, SLS was applied to covered skin and left on for 4 hours, which does not reflect real-world use.
- Formulation matters more than individual ingredients, so the mere presence of sulfates does not necessarily equate to a harsher shampoo. For example, the addition of soothing and moisturizing ingredients in a sulfate-containing shampoo may reduce the chance of drying or irritating the scalp.
Products with milder surfactants as well as soothing and moisturizing ingredients may have less potential to cause skin reactions in those with dry, flaky, irritated scalp. Examples of surfactants that may be better suited for sensitive scalp:
- Cocamidopropyl betaine
- Cocamidopropyl betaine + SLES
- Cocamidemonoethanolamide
- Cocoglucoside
- Glucosides (decyl, lauryl, caprylyl)
- Sodium cocoyl isethionate
- Sulfosuccinates
- Acylsarcosinates
- Isethionates
Examples of soothing and moisturizing agents:
- Aloe vera extract
- Bisabolol
- Ceramides
- Chamomile
- Cocoa butter
- Fatty acids (e.g. linoleic acid)
- Glycerin
- Panthenol
- Plant oils (e.g. jojoba, argan oil)
- Shea butter
It’s still important to note that non-sulfate surfactants may still cause reactions. Cocamidopropyl betaine has been reported to be an allergen (1-2% of patch-tested patients). Alkyl glucosides, made with coconut oil and a starch, have also been documented as an allergen (2% of patch-tested patients). Nevertheless, like all potential allergens in cosmetics, the incidence of skin reactions in the general population is not that common, but can increase in incidence in those with underlying skin disorders or impaired barriers. Another thing to remember is that very mild surfactants are less efficient in removing dirt, grime, and buildup in hair, so washing once in a while with a shampoo with stronger surfactants (offset by soothing, and moisturizing ingredients) would be helpful.
Conditioning agents, by making hair more manageable (easier to comb hair and be less traumatic to the scalp), may indirectly help with the scalp irritation:
- Behentrimonium chloride
- Cetrimonium chloride
- Cetyl alcohol
- Polyquaternium-69/70/8/10
- Silicones (dimethicone, amodimethicone)
- Stearamidopropyl dimethylamine
- Stearyl alcohol
- Isethionates
As previously mentioned, a dry, flaky, and irritated scalp may be due to a barrier dysfunction, which can lead to increased penetration of irritants and allergens. To avoid this, it is wise to avoid common sensitizers in hair care products, particularly if the patient has sensitive skin elsewhere or a skin condition such as atopic dermatitis.
Common sensitizers include fragrance, preservatives like isothiazolinones, sulfates, sulfonates, and alcohol. While skin reactions to these sensitizers are not common in the general population, they can increase in those with skin disorders or impaired barriers. It is recommended to patch test products at home before use. For those experiencing recurring scalp problems, an in-office patch test can identify specific ingredients that may be causing the reaction, and avoidance can be suggested accordingly.
Other triggering factors include environmental agents (ultraviolet radiation, extremes of temperature, cold weather, low humidity, chlorine in water, and pollutants).
General principles for managing a dry, irritated scalp:
I. Appropriate treatment of the underlying condition, if any.
II. Support of the skin barrier function
III. Removal or avoidance of potential aggravating factors
