What is the cause of chapped lips?

Dry air, whether it's due to the climate or home heating, is a major cause of chapped lips. Indeed, when the humidity in the air is low, the skin of the lips, which is already almost devoid of sebaceous glands and hydrolipidic film, rapidly loses its water content through a phenomenon known as insensible water loss. This natural evaporation is exacerbated by dry air, which draws moisture from the superficial layers of the epidermis. The result: lips become dry, rough, and more vulnerable to cracks.

Furthermore, in winter, the lack of humidity in the outdoor air often combines with the warm, dry air of heated interiors, thereby exacerbating the dehydration of the lips. This issue, which also affects the skin of the face and hands, particularly impacts the lips, whose horny layer is thinner than on the rest of the body. A similar phenomenon is observed in hot and dry climates, where prolonged exposure to arid winds or air conditioning in enclosed spaces amplifies the water loss from the lips and can lead to chapping.

Even though it may seem like it alleviates dryness, the habit of licking one's lips can actually exacerbate chapping. Indeed, when we lick our lips, saliva, although moist at the time of application, causes a rapid dehydration of the skin when it evaporates. A vicious cycle then sets in: saliva temporarily moisturizes the skin, but its evaporation accelerates the loss of hydration, which intensifies the sensation of dryness. As a result, we lick our lips again to relieve the discomfort, thereby worsening the chapping and perpetuating the cycle of dehydration.

Furthermore, saliva, primarily composed of water, also contains enzymes, such as amylase, which can alter the structure of the skin on the lips. These enzymes, designed to break down food in the mouth, can destabilize the skin barrier when frequently applied to the lips. Thus, saliva does more than just dehydrate the lip skin: it modifies its lipid composition, weakening its barrier function and increasing its vulnerability to external aggressions.

If you experience a feeling of dryness on your lips, it is better to apply a emollient lip balm.

Chapped lips can sometimes be a sign of a nutritional deficiency. Indeed, certain nutrients are closely involved in maintaining skin hydration and cellular regeneration, and their absence can disrupt these processes and increase lip sensitivity. Among the nutrients associated with chapped lips, we notably find vitamins A, B2, B6, C, and E, and zinc. Each has a different mode of action.

For instance, Vitamin A plays a role in the renewal of cells and in the repair of skin tissues. A deficiency in this vitamin can weaken the skin and promote chapped lips. As for Vitamin B2, it helps combat dehydration. Vitamin B6, on the other hand, is involved in the synthesis of collagen and a deficiency in this vitamin can weaken the skin's ability to maintain its elasticity. Lastly, the Vitamin C, well-known for its antioxidant properties, is also essential for the production of collagen and the repair of skin tissues.

Adopting a balanced diet, essential for maintaining health, is also important for preventing chapped lips.

Often underestimated, stress can also impact the health of the lips and play a role in their chapping. One of its main effects on the skin is the increased production of cortisol. When this hormone is synthesized in excess, it can weaken the skin barrier by reducing the skin's ability to retain water. Drier, the skin of the lips is indeed more likely to crack. Moreover, stress can alter behaviors and increase the tendency to frequently lick the lips, which, as previously explained, dries out the skin in this area and promotes chapped lips.

Finally, stress impacts the immune system and weakens it, which can make the skin more susceptible to infections and inflammations. Therefore, when the lips are already damaged by cold or dehydration, stress can exacerbate this situation by slowing down the healing process and making the chapping persistent.

Allergies can also play a role in the occurrence of chapped lips. One common form of allergy is contact eczema. This reaction is triggered by the contact between the skin and a substance it cannot tolerate. For instance, it could be an allergen contained in a cosmetic product, such as a lip balm or toothpaste. Among the most common allergens are fragrances, certain preservatives, or even essential oils. It's worth noting that allergic reactions are not always immediate and can appear several hours, or even a few days after exposure to the allergen.

Irritants, which are different from allergens, can also be contributing factors to chapped lips. For instance, certain foods, such as citrus fruits, are known to irritate the skin and cause tingling sensations. The acids present in these fruits can disrupt the skin barrier and cause micro-traumas, thereby increasing the vulnerability of the lips and their risk of becoming chapped. Certain cosmetics, containing drying ingredients, such as alcohols, can also be the source of irritations.

Another potential cause of chapped lips: infections. One of the most common is oral herpes, caused by the herpes simplex virus. This viral infection frequently affects the lips and causes the appearance of small, painful, fluid-filled blisters. Oral herpes can also weaken the structure of the lips and cause cracks, making the skin even more vulnerable to dehydration and secondary infections. This infection is often triggered by cold, stress, prolonged exposure to the sun, or even lip dehydration.

Less common than viral or bacterial infections, fungal infections can also be responsible for chapped lips. Notably, there is candidiasis, caused by the fungus Candida albicans, which presents with redness and irritation, sometimes accompanied by cracks. Candidiasis can be the cause of a perlèche, a painful inflammation localized at the fold of the lip corner. An antifungal treatment is then necessary to curb the infection.

Finally, lips can become chapped as a result of taking certain medications. One of the most common groups responsible for chapped lips are retinoids, specifically isotretinoin, an oral medication. Used to treat acne, this derivative of vitamin A accelerates cell renewal and drastically reduces sebum production by the sebaceous glands, thus eliminating part of the hydrolipidic film that protects the skin. Patients undergoing this treatment often observe a drying of their skin, particularly on the lips, which can lead to chapped lips. To counterbalance this side effect, it is recommended to regularly apply a rich lip balm.

Note : Certain diuretics, antibiotics, antidepressants, and antihistamines are also likely to cause lip dehydration, which can lead to chapped lips.