Eczema is a chronic skin disease that first manifests as patches of dry or red itchy skin. Scratching the skin damages its surface and can worsen the rash. Eczema can begin very early in life, and most people who get eczema will have it before they turn 5 years old. Eczema tends to come and go, often without warning. Some patients note seasonal variation—for example, worse in the summer or winter, while others do not. There can also be long intervals between episodes, sometimes spanning years or decades.
The basic abnormality in eczema is excessive trans-epidermal water loss (i.e., the skin in the affected area can’t retain the water in its cells), and this causes the skin to be drier than normal. For this reason, the basic tenets of treatment revolve around prevention of overdrying the skin and protecting it from irritants. These goals are usually accomplished by instructing patients to limit their bathing and avoid harsh soaps and chemicals. In simple terms, generally speaking, water—by itself—is an enemy of dry skin because excessive bathing and water exposure will actually cause more dryness and the eczema to worsen (or, at best, to remain stable). It will never make the eczema better.
As eczema is a condition of excessive trans-epidermal water loss, salinated water is much worse than non-salinated water. Salinated water will excessively draw moisture from the skin due to osmosis; that is, the water will “suck” water from skin in an attempt to bring the extremely salinated ocean water to equilibrium (equal salinity) with the very mildly salinated water in the human. This is the same mechanism involved as when we get thirsty and bloated from eating salty foods.
In addition to the above measures, either over-the-counter or prescription emollients (moisturizers) are essential and are an important part of daily skin care. If eczema flares, i.e., there is more itching or the appearance of a rash, intervention with prescription medications such as topical corticosteroid creams, antihistamines, antibiotics, calcineurin inhibitors, or immunomodulatory agents may be necessary, depending on the severity of the flare.
Eczema medical expert witness specialties include dermatology, dermatopathology, and pathology.