Skin hydration is a complex process that must be performed from inside & outside our bodies. Basically speaking, one has to differentiate between dehydrated skin which is manifested by loss of resilience and dry skin which is devoid of natural oily secretions and appears dull and/or scaly.

Skin hydration is mainly maintained by the presence of the skin barrier which is our body's outermost protective organ functioning via maintaining five barrier functions: Permeability Barrier, Anti-Microbial Barrier, Anti-Oxidant Barrier, Immune Response Barrier & Photoprotection Barrier resulting in prevention of the loss of fluids, electrolytes, and other molecules from within the body and prevention of penetration by microorganisms, toxic materials, and portion of UV radiation by the stratum corneum.

This is carried out by the so-called “Brick & Mortar” Module, where the corneocytes serve as the bricks while the hydrophobic lipids in the extracellular space serve as the Mortar. This process is in continuous production and renewal with the maturation of keratinocytes from the basal layer in their journey resurfacing upwards to be corneocytes.

Skin hydration can be affected negatively by many factors including:
1. Extrinsic factors as exposure to temperature extremes especially in humid environments, prolonged sun exposure, repeated exfoliation, harsh cleansers, excess exposure to A/C and repetitive prolonged bathing.
2. Intrinsic factors as excess caffeine, sodium, sugar and fat intake.

On the other hand, it can be boosted by many modalities including:
1. Topical application of humectants, moisturizers and oils and products enhancing epidermal ceramides and dermal hyaluronic acid.
2. Systemic intake of water and vitamins as A & C.

Poor maintenance of the skin barrier can result in skin barrier defect which has a role in different dermatoses via three different scenarios that result in increased skin sensitivity:
1. Skin Barrier Defect is the cause of the disease as in cases of atopic dermatitis.
2. Skin Barrier Defect results as a sequelae of the already present disease as in cases of auto-immune bullous disorders.
3. Skin Barrier Defect presence aggravates the already present disease as in cases of acne and rosacea.

The cornerstone of skin barrier regulation and repair is through the use of moisturizers. The importance of moisturizers shall not be underestimated and the benefit of a well-planned moisturizer regimen for skin barrier regulation should be highlighted as it encompasses many benefits as smoothing & hydrating the skin in addition to reduction of fine lines, better wound healing with concomitant anti-inflammatory and antipruritic effect resulting in improved quality of life.

Moisturizers can be classified according to their components into emollients, humectants, occlusives and protein rejuvenators, which serves valuably if positioned probably in different skin disorders and conditions as they have different mechanisms of action, hence different indications.

Emollients can be found in different formulations to suit different skin types, sites and situations including lotions, creams, ointments and gels and they can have many essential ingredients as ceramides, hyaluronic acid and niacinamide.

Based on that, we can easily conclude that maintenance of the skin barrier is a must for maintenance of skin hydration, maintaining skin health and youthfulness in addition to combating different skin illnesses.