Caring for one’s hair is just as important as caring for one’s face, but often gets less attention. Understanding what constitutes a good shampoo is an important part of making sure your hair stays healthy and voluminous.
To help you navigate the world of hair care products, we introduce you to the basics you need to know.
How should a shampoo function?
A shampoo is expected to cleanse the scalp and hair of dirt, sebum, sweat, dead skin cells and environmental pollutants. It also should remove greasy residues from hair care products such as oils, gels and sprays.
While most products can accomplish a thorough cleanse, the real challenge lies in removing just enough sebum to allow the hair to be clean without drying it out.
This explains why most shampoo formulations have a secondary function of smoothing the hair’s surface and imparting lustre, smoothness, buoyancy and volume.
Typical shampoos contain 10 to 30 ingredients. These include: cleansing agents (surfactants), conditioning agents, special care ingredients, and additives. The surfactants are responsible for cleansing hair while the conditioners and other ingredients do the rest.
Types of surfactants
A surfactant is often amphiphilic, meaning its molecules contain both lipophilic (oil-attracting) and hydrophilic (water-attracting) parts. The oil-attracting parts bind to sebum while the water-loving sites parts to water. Such a mechanism allows sebum to be removed when in contact with water.
The type of surfactants used in shampoos is classified according to their hydrophilic polar group. The four common categories of shampoo surfactants are anionics, cationics, non-ionics and amphoterics. Most formulas rely on two types of surfactants.
The surfactant listed first in a shampoo’s ingredient list denotes the primary cleanser and also the ingredient in the highest concentration. The surfactant listed second is the secondary cleanser; this is often added to offset the weaknesses of the first surfactant.
Anionic sufactants are named for their negatively charged hydrophilic (water-loving) parts. Derived from fatty alcohols, they are good at removing sebum from the scalp. However, excessive cleansing with anionic surfactants leaves the hair harsh, rough, dull, frizzy and prone to tangling.
In contrast to anionic surfactants, cationic sufactants have a positively charged element. Cationic surfactants are poor cleansers and do not lather well. They are also not compatible with anionic surfactants. However, they are excellent at keeping chemically damaged hair soft and manageable. As a result, shampoos for damaged or coloured hair often include cationic surfactants. Examples include long-chain amino esters, ammonioesters, and cetyltrimethylammonium chloride.
With both positively and negatively charged groups, amphoteric surfactants foam well and condition the hair. In addition, they do not cause stinging in the eyes and are gentle on the skin/scalp barrier, making them ideal for mild shampoos. Examples are betaine, sulfonate betaine, amphoteric acetate/diacetate.
Nonionic sufactants do not have a charged group and hence are compatible with any surfactant. Nonionic surfactants are the mildest type of surfactant but lather poorly. Such surfactants are often used in baby shampoos. Examples are fatty alcohol ethoxylates, sorbitan ether esters, and alkyl polyglucosides.
Conditioners (in shampoo formulations)
Shampoo formulations tend to add hair-conditioning ingredients to impart manageability, gloss and antistatic properties to the hair. Many are noted as ‘2 in 1’ to indicate the presence of both cleansing and conditioning benefits.
Examples of conditioning ingredients are fatty substances such as vegetable oils, wax, lecithin and lanolin derivatives, protein by-products (collagen, silk, animal proteins) and silicones.
Silicones add lubricity to the hair and reduce friction that arises from combing. They make it easier to comb through and detangle strands and prevent them from becoming frizzy.
Protein substances found in conditioners function by temporarily mending split ends and holding the hair fragments together until the next shampooing takes place.
To stand out in the market, certain shampoos may offer other attractive ingredients such as panthenol, pro-vitamins or botanicals such as tea tree oil. However, given that the contact time of the product with the scalp and hair is brief, it is unlikely that these provide significant clinical benefits. Such additives function more as a marketing tools.
Shampoos for special conditions
For shampoos that target conditions such as dandruff or seborrhea (oily scalp), active ingredients are added.
Dandruff is often due to the overgrowth of a yeast called Malassezia spp. Anti-dandruff shampoos rely on ingredients that can inhibit the overproduction of yeast cells. Such ingredients include zinc pyrithione, ketoconazole and selenium disulphide.
For patients with oily scalps, coal tar can be an effective ingredient in reducing sebum production.
For deep cleansing of the scalp with pharmaceutical grade ingredients, consider Deep Cleanse Shampoo. It degreases oily scalps, calms irritated or sensitive scalp problems and improves hair loss control, This shampoo also contains zinc pyrithione to target dandruff, thus suitable for many hair types.
Seborrhoeic or seborrheic dermatitis is a common, chronic or relapsing form of eczema/dermatitis. The condition mainly affects the sebaceous, gland-rich regions of the scalp, face, and trunk. There are infantile and adult forms of seborrheic dermatitis. It is sometimes associated with psoriasis (sebopsoriasis). Seborrheic dermatitis is also known as seborrheic eczema.
Dandruffalso known as pityriasis capitis is considered to be an uninflamed form of seborrheic dermatitis. Scattering within hair-bearing areas of the scalp, dandruff of such presents as itself as bran-like scaly patches.
Although the cause of seborrheic dermatitis is not completely understood, it is associated with proliferation of various species of the skin commensal Malassezia, in its yeast, non-pathogenic form. Its metabolites (such as the fatty acids oleic acid, malssezin, and indole-3-carbaldehyde) may cause an inflammatory reaction. Differences in skin barrier lipid fuction and content may account for individual presentations.
Adult seborrheic dermatitis tends to begin in late adolescence. It is less common in females than in males and most common amongst young adults and in the elderly.
Factors sometimes associated with severe adult seborrheic dermatitis:
A family history of psoriasis or familial tendency to seborrheic dermatitis
Oily skin (seborrhoea)
Lack of sleep, and stressful events.
Immunosuppression: organ transplant recipient, human immunodeficiency virus (HIV) infection and patients with lymphoma
Neurological and psychiatric diseases: congenital disorders such as Down syndrome, depression, epilepsy, facial nerve palsy, tardive dyskinesia, parkinson disease, spinal cord injury
Psoralen and ultraviolet A (PUVA) therapy used in treatments for psoriasis
Infantile seborrheic dermatitis is the type of seborrhoeic dermatitis that affects babies under the age of 3 months and usually resolves by 6–12 months of age. It causes cradle cap, the diffuse greasy scaling on scalp. The rash may spread to affect armpit and groin folds resulting in a type of napkin dermatitis. They are characterised by their flaky or peeling salmon-pink patches. Since it is not itchy, babies often appear undisturbed by the rash, even when generalised.
Typical featuresof seborrheic dermatitis
Often affects the upper trunk, facial areas such as within eyebrows, around the nose and behind ears and scalp
Winter flares, improving in summer following sun exposure
Minimal itch most of the time
Combination oily and dry mid-facial skin
Ill-defined localised scaly patches or diffuse scale in the scalp
Blepharitis: scaly red eyelid margins
Ill-defined, thin, scaly and salmon-pink plaques in skin folds on both sides of the face
Ring-shaped or petal-shaped flaky patches on anterior chest or hair-line
Rash in armpits, under the breasts, in the groin folds and genital creases
Superficial folliculitis (inflamed hair follicles) on cheeks and upper trunk
Pityriasiform seborrhoeide is a form of extensive sebrrhoeic dermatitis that affects the scalp, neck and trunk.
Seborrheic dermatitis is often diagnosed by its clinical appearance and behaviour. This is because Malassezia is a normal component of skin flora. Due to this, their presence on microscopy of skin scrapings is often not diagnostic.
Histological findings specific to seborrheic dermatitis are as follows:
Although skin biopsy may be helpful, it is rarely indicative.
superficial perivascular and perifollicular inflammatory infiltrates
parakeratosis around follicular openings.
Treatment of seborrheic dermatitis often involves several of the following options:
Keratolytics can be used to remove scale when necessary, eg salicylic acid, lactic acid, urea, propylene glycol
To reduce Malassezia, topical antifungal agents such as ketoconazole, or ciclopirox shampoo or and/or cream are applied. It is important to note that some strains of Malassezia are resistant to azole antifungals. In such cases, it is advised to try zinc pyrithione or selenium sulphide, under a dermatologist supervision.
Mild topical corticosteroids are prescribed for 1–3 weeks to reduce the inflammation of an acute flare
Topical calcineurin inhibitors (pimecrolimus cream, tacrolimus ointment) are indicated if topical corticosteroids are often needed, as they have fewer adverse effects on facial skin
In resistant cases in adults, oral itraconazole, tetracycline antibiotics or phototherapy may be recommended. Low dose oral isotretinoin has also been shown to be effective for severe or moderate seborrheic dermatitis.
Anti-dandruff shampoos containing zinc pyrithione and salicylic acid such as the Deep Cleanse Shampoo should be used daily.
Other medicated shampoos containing selenium sulfide, coal tar, ciclopirox and ketoconazole should be used twice weekly for at least a month.
Steroid scalp applications are seen to reduce itching. These should be applied daily for a few days every so often.
Calcineurin inhibitors such as tacrolimus can be used as steroid alternatives.
Coal tar cream can be applied to scaling areas and removed several hours later by shampooing.
Combination therapy is often advisable.
Treatment for face, ears, chest and back
Using a non-soap cleanser, cleanse the affected skin thoroughly once or twice each day.
Apply ciclopirox cream or ketoconazole once daily for 2 to 4 weeks, repeated as necessary.
Hydrocortisone cream can also be used, applied up to twice daily for 1 or 2 weeks. Occasionally a more potent topical steroid may be prescribed.
Topical calcineurin inhibitors such as pimecrolimus cream or tacrolimus ointment may be used instead of topical steroids.
A variety of herbal remedies are commonly used, but their efficacy is uncertain.
Regular washing of the scalp with baby shampoo or aqueous cream is followed by gentle brushing to clear the scales.
White petrolatum may be useful.
Depending on the extent of the rash, topical antifungals are often prescribed.
By Dr. Teo Wan Lin, Consultant Dermatologist at TWL Specialist Skin & Laser Centre
In the third instalment of my series on dealing with hair loss in Singapore as a dermatologist, I’m going to discuss dandruff and scalp sensitivity. This is one of the commonest scalp complaints that my patients have in conjunction with hair loss symptoms and leaves many of them wondering if it is the cause of their hair loss problem.
1. What is dandruff and what causes it?
Flaking on the scalp and white scales found on one’s clothes are one of the first symptoms of dandruff. This is lay speak for any form of scalp inflammation that causes the cell turnover rate on the scalp to increase abnormally. Dead skin cells, which are rapidly shed from the cell turnover, in turn constitute the white scales observed as the primary symptom of dandruff. There are several medical conditions that can result in this, the commonest being the following: scalp psoriasis, seborrheic dermatitis and scalp eczema.
2. Do I have a sensitive scalp or is it a symptom of another condition?
Do you have itch, redness or pain on your scalp? You may have an undiagnosed inflammatory scalp disease. Scalp “sensitivity” without any underlying scalp condition is a very rare condition attributed to abnormal nerve sensations known as scalp dysaesthesia. It is far more common to have an underlying cause such as seborrheic dermatitis, which is due to proliferation of a yeast known as malessezia furfur in an individual with excess production of oil. It is also commoner in tropical and humid climates such as Singapore, as it encourages this yeast to grow.
Otherwise, malessezia is an inhabitant of one’s skin and scalp. Under normal conditions, it does not cause any issues. However, under humid and sweaty environments, this yeast can proliferate to cause scalp inflammation and flaking. Dandruff is observed as a result. If you have scalp flaking which does not respond to over the counter anti-dandruff shampoos, such as those containing zinc pyrithone which is anti-fungal, promptly seek the care of an accredited dermatologist rather than self medicate or DIY.
Other causes of scalp inflammation would be scalp eczema, which is due to an excessively dry scalp/skin condition. For example, scalp psoriasis, which may be the case especially if one has a family history of psoriasis or rashes on the body. If you have been in contact with a ringworm infected cat or dog, also do have your scalp and skin checked by a dermatologist as these infections are contagious and could also cause a form of scalp inflammation presenting as a red, scaly and itchy patch with hair loss.
3. Is my sensitive scalp and dandruff causing hair loss?
Most cases of scalp inflammation due to eczema, seborrheic dermatitis, scalp folliculitis or psoriasis should not cause hair loss. However severe inflammation can push the hair growth cycle into a stage of telogen effluvium which is when hair reaches the end of its cycle and falls out, similar to hair loss that occurs after a major illness or post-pregnancy. In addition, if one picks and peels off crusted areas over the scalp this can also cause damage to the hair root and lead to hair loss.
There are other causes of hair loss such as alopecia areata, which is an autoimmune disorder causing one’s immune system to attack hair follicles, leading to hair loss. This usually has no symptoms other than the appearance of round patches of hair loss over one’s scalp. Scarring causes of hair loss include folliculitis decalvans, which is the end-stage of a type of scalp folliculitis, whereby the hair follicles themselves are constantly inflammed and infected. Children may be more susceptible to tinea capitis, which is a fungal scalp infection that can lead to scarring hair loss if untreated.
Meet with Dr. Teo Wan Lin, founder and Specialist Consultant Dermatologist of TWL Specialist Skin & Laser Centre, an accredited dermatologist specialising in medical and aesthetic dermatology. She integrates her artistic sensibility with her research background and specialist dermatologist training, by means of customised, evidence-based aesthetic treatments using state-of the-art machines, injectables (fillers and toxins). These work synergistically with her proprietary line of specialist dermatologist grade cosmeceuticals, Dr.TWL Dermaceuticals, which include sensitive scalp and hair loss treatments.
To book an appointment with Dr. Teo, call us at +65 6355 0522, or email firstname.lastname@example.org. Alternatively, you may fill up our contact form here.