Keratosis pilaris: what you need to know about this skin condition.

The keratosis pilaris is a benign skin condition. The symptoms of keratosis pilaris are readily identifiable. It is recognised by the small flesh-coloured bumps that it triggers, sometimes surrounded by pink or brown. These lesions may be described as white bumps on the arms, small red bumps on the legs or bumps on the thighs. Although these imperfections can occur on various parts of the body, they typically appear on the outer aspects of the arms, thighs and calves. In these areas, the skin is dry, rough in appearance and the texture uneven, which many perceive as numerous tiny itchy bumps on the arms or dry skin bumps.

Keratosis pilaris typically resolves spontaneously by one’s twenties. However, in some cases it persists long-term and can cause discomfort and self-consciousness, particularly in summer when the weather invites one to reveal one’s arms and legs. Moreover, although benign, keratosis pilaris can sometimes cause itching. If inflammation follows scratching, the small follicular plugs may develop a red appearance. In certain instances, keratosis pilaris leads to an increase in ingrown hairs. It is also worth noting that it can affect very young children. Keratosis pilaris in babies is often mistaken for other types of small bumps on the body

Keratosis pilaris results from a dysregulation of the keratinisation process, more precisely an excessive production of keratin by keratinocytes. Trapped in hair follicles, the surplus keratin accumulates and eventually obstructs them. Several studies have been conducted to understand the origin of keratosis pilaris and scientists ultimately established the hereditary nature of this condition. It is inherited in an autosomal dominant manner, meaning that the mutation is present on a non-sex chromosome and that only a single copy of the gene needs to be affected. A mutation in the FLG gene is thought to be responsible. This gene encodes filaggrin, a protein associated with keratin in the epidermis that contributes to its barrier function.

In addition to this well-documented genetic component, several additional factors are suspected of contributing to the development of keratosis pilaris. Some hormonal variations, notably during adolescence, pregnancy or certain phases of the menstrual cycle, could influence keratinisation and encourage the formation of the characteristic keratin plugs of keratosis pilaris. Some research teams also suggest a possible link with insulin resistance: an excess of circulating insulin could disrupt keratinocyte differentiation, but this mechanism remains theoretical.

Similarly, an unbalanced diet, deficient in fatty acids or in vitamins involved in barrier function, could encourage follicular blockage. It must be emphasised that these are merely hypotheses and that further research is still required to draw firm conclusions.

Finally, individuals affected by atopic dermatitis or ichthyosis appear to be particularly predisposed to developing keratosis pilaris. These conditions indeed share common pathophysiological mechanisms, notably a disruption of the skin barrier, pronounced dryness and a keratinisation abnormality, which together create a favourable environment for the formation of follicular plugs.

To alleviate the symptoms of keratosis pilaris, it is beneficial to adopt a tailored skincare regimen.

• Regular and gentle cleansing of the skin.

  If cleansing your skin is essential, it is important to do so with gentle products that do not harm the skin barrier, which is already fragile in cases of keratosis pilaris. To achieve this, we recommend selecting a mild, hydrating cleanser, such as a dermatological cleansing bar. Formulated at the skin’s physiological pH, this type of product helps maintain hydration of the stratum corneum and is suitable for all skin types, including the most sensitive.

• Exfoliation once or twice a week.

  If all skin types benefit from using an exfoliating treatment once or twice a week, those affected by keratosis pilaris particularly need it. Indeed, these products help remove dead skin cells accumulated on the surface of the skin and thus contribute to unclogging hair follicles. Additionally, exfoliating treatments aid in softening the epidermis and in combating the roughness caused by keratosis pilaris.

• Daily hydration.

  Daily skin hydration is not reserved for those with dry skin. In addition to protecting the epidermis from external aggressors and limiting water loss, the application of emollients helps to soften the skin and reduce roughness. These properties are particularly relevant in the context of keratosis pilaris. Alongside a moisturising cream or balm, applying plant-based oils and butters, such as the argan oil and the mango butter, are also beneficial.

• Avoid handling keratin plugs.

  Although it may sometimes be tempting, it is strongly recommended not to scratch, pierce or attempt to extract the tiny keratin plugs caused by keratosis pilaris. This could weaken the skin barrier and provoke micro-inflammations and redness. Moreover, depending on your phototype, there is a risk of hyperpigmentation or post-inflammatory erythema. To remove keratin plugs, it is preferable to opt for exfoliating treatments.

It is not necessary to treat keratosis pilaris as it is harmless to health. Of course, you can certainly choose to remove it for aesthetic reasons.

It is important to note that most treatments aim to alleviate the symptoms of keratosis pilaris, without, however, completely eliminating them. Among the active compounds studied in scientific research for their keratolytic properties, one may particularly mention retinoids, such as tretinoin and adapalene, azelaic acid and calcipotriol, a derivative of vitamin D. The topical application of creams containing these ingredients helps to improve the appearance of keratosis pilaris, but it cannot eliminate it.

A more effective solution for combating keratosis pilaris is laser therapy. However, it should be noted that this technique is not suitable for pregnant women or for individuals undergoing photosensitising treatment. Several aesthetic centres offer laser sessions aimed at eliminating keratosis pilaris. The type of laser encountered in these centres varies; it may be an Nd:YAG laser, a CO₂ laser or even a pulsed-light laser. These different lasers have comparable efficacy against keratosis pilaris. While the results after several laser sessions are often satisfactory, they are unfortunately temporary. Indeed, once the sessions are discontinued, a relapse is generally observed.

Several studies have evaluated the efficacy of laser therapy for alleviating keratosis pilaris. One very recent study investigated the effects of the 755 nm alexandrite laser and compared it with simple daily moisturisation. The 21 participants underwent four laser sessions on one arm, each three weeks apart. Four weeks after the final treatment, both physician and patient assessments demonstrated a marked improvement on the treated side, with a significant decrease in roughness and redness. Additional examinations (dermoscopy, high-frequency ultrasound and biopsies) confirmed these findings, showing a more pronounced reduction of keratinised plugs on the laser-treated side. However, three cases of post-inflammatory hyperpigmentation, fortunately reversible, were observed.

Overall, the study concludes that the 755 nm alexandrite laser is an effective option to attenuate the characteristic roughness and redness of keratosis pilaris.

Hair removal and keratosis pilaris do not always go hand in hand, and a poor technique can quickly lead to the formation of ingrown hairs. To prevent them, we recommend avoiding the electric epilator and waxing. Although these hair removal methods are convenient and widely used to space out sessions, they encourage the occurrence of ingrown hairs by pulling the hair directly from the follicle. Sometimes, hindered by excess keratin, the hair does not regrow straight but curves into the epidermis, becoming ingrown. This then leads to inflammation and a small red bump, similar to those caused by keratosis pilaris.

In cases of keratosis pilaris, it is generally recommended to use depilatory cream or laser hair removal.

The depilatory cream and laser treatment are generally recommended for individuals with keratosis pilaris. Indeed, the former does not affect the hair bulb or subsequent hair growth. Depilatory cream works by targeting keratin and softening the hairs, which then shed after a few minutes. Laser treatment, effective in the long term, operates on the principle of selective photothermolysis. The infrared beams it emits target the melanin concentrated in the hair shaft and convert into heat to destroy the entire follicle. Suitable for all skin phototypes, the laser hair removal is nonetheless not feasible in cases of very light hair, during pregnancy, or when using a photosensitising medication.

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