What is dermatitis?

Dermatitis is a general term used to describe inflammation of the skin. It encompasses a range of skin conditions characterized by redness, itching, swelling, and sometimes blistering or flaking of the skin. Dermatitis can occur anywhere on the body and may be acute (short-term) or chronic (long-term). There are several types of dermatitis, each with its own causes and symptoms. Some common types of dermatitis include:


  • Atopic Dermatitis (Eczema): Atopic dermatitis, often referred to as eczema, is a chronic inflammatory skin condition characterized by dry, itchy, and inflamed patches of skin. It typically begins in infancy or childhood and may persist into adulthood. People with atopic dermatitis may experience flare-ups triggered by factors such as allergens, irritants, stress, or changes in weather.


  • Contact Dermatitis: Contact dermatitis occurs when the skin comes into contact with a substance that irritates or triggers an allergic reaction. There are two main types of contact dermatitis: irritant contact dermatitis, which occurs when the skin is exposed to irritants such as harsh chemicals or detergents, and allergic contact dermatitis, which occurs when the skin develops an allergic reaction to a specific substance, such as latex, nickel, or certain cosmetics.


  • Seborrheic Dermatitis: Seborrheic dermatitis is a common chronic inflammatory skin condition characterized by red, greasy, and scaly patches of skin, particularly on areas of the body with a high density of oil glands, such as the scalp, face, and upper chest. It may be associated with factors such as hormonal changes, stress, or the overgrowth of yeast on the skin.


  • Nummular Dermatitis: Nummular dermatitis, also known as discoid eczema, is a chronic inflammatory skin condition characterized by coin-shaped patches of red, itchy, and scaly skin. It may be triggered by factors such as dry skin, irritants, or allergic reactions.


  • Dermatitis Herpetiformis: Dermatitis herpetiformis is a chronic inflammatory skin condition characterized by intensely itchy and blistering skin lesions, often occurring in symmetrical patterns on the elbows, knees, buttocks, and scalp. It is associated with an autoimmune reaction to gluten ingestion in individuals with celiac disease.


What is the relationship between dermatitis and oxidative stress?

The relationship between dermatitis and oxidative stress is multifaceted, as oxidative stress can both contribute to the development of dermatitis and exacerbate its symptoms. Here’s how oxidative stress influences dermatitis:


  • Inflammation: Oxidative stress can induce and perpetuate inflammation in the skin, which is a hallmark feature of dermatitis. Reactive oxygen species (ROS) generated during oxidative stress can activate inflammatory pathways and stimulate the production of pro-inflammatory cytokines, chemokines, and inflammatory mediators in the skin. This inflammatory response leads to redness, swelling, itching, and other symptoms characteristic of dermatitis.


  • Skin Barrier Dysfunction: Oxidative stress can impair the function of the skin barrier, which plays a crucial role in protecting the skin from external irritants, allergens, and pathogens. ROS can damage lipids, proteins, and DNA in the skin cells, including keratinocytes, which are essential for maintaining the integrity of the skin barrier. Disruption of the skin barrier function can increase susceptibility to irritants, allergens, and microbial infections, exacerbating dermatitis symptoms and promoting disease progression.


  • Oxidative Damage to Skin Cells: Oxidative stress can cause oxidative damage to various components of skin cells, including lipids, proteins, and DNA. Lipid peroxidation, the process by which ROS attack and degrade cell membrane lipids, can disrupt the structure and function of cell membranes, leading to increased permeability and loss of cellular integrity. Oxidative damage to proteins and DNA can impair cellular function, interfere with cell signaling pathways, and promote cell death or dysfunction, contributing to the pathogenesis of dermatitis.


  • Impaired Antioxidant Defenses: Antioxidants play a critical role in neutralizing ROS and protecting the skin from oxidative damage. However, oxidative stress can overwhelm the antioxidant defense mechanisms in the skin, leading to a state of antioxidant imbalance. Depletion of antioxidants such as vitamins C and E, glutathione, and superoxide dismutase can further exacerbate oxidative stress and inflammation in the skin, exacerbating dermatitis symptoms.


  • Chronicity and Recurrence: Oxidative stress can contribute to the chronicity and recurrence of dermatitis by promoting tissue damage, inflammation, and immune dysregulation in the skin. Chronic exposure to oxidative stressors, such as UV radiation, pollutants, or psychological stress, can exacerbate dermatitis symptoms and prolong the duration of flare-ups. Oxidative stress-induced alterations in immune function and skin barrier integrity may also contribute to the persistence and recurrence of dermatitis over time.


Overall, oxidative stress plays a significant role in the pathogenesis and exacerbation of dermatitis by promoting inflammation, impairing skin barrier function, causing oxidative damage to skin cells, and disrupting antioxidant defenses.