In the context of dermatitis, the sequence of events between a compromised skin barrier and inflammation can vary depending on the type of dermatitis. However, generally speaking, the compromised skin barrier is often the initial event that leads to inflammation.
Compromised Skin Barrier
Initial Barrier Dysfunction: Many forms of dermatitis, especially atopic dermatitis (eczema), begin with a compromised skin barrier. This can be due to genetic factors, environmental factors, or a combination of both. For instance, mutations in the filaggrin gene, which is important for skin barrier function, can be found in individuals with atopic dermatitis (eczema). Irritating products (e.g. exfoliating acids, physical exfoliaters, synthetic fragrances and drying alcohols) can also disrupt the skin barrier.
Increased Permeability: When the skin barrier is compromised, it becomes more permeable to irritants, allergens, and pathogens. This increased permeability allows these external substances to penetrate the skin more easily and create inflammation.
Inflammation
Immune Response Activation: The penetration of irritants, allergens, or pathogens triggers an immune response. The immune system recognizes these foreign substances as threats and, as mentioned above, initiates an inflammatory response to combat them.
Inflammatory Cascade: The immune response involves the release of various inflammatory mediators, such as cytokines and chemokines, leading to the characteristic redness, swelling, and itching associated with dermatitis. This inflammation can lead to further damage to the skin barrier.
Conclusion
While the exact sequence can be influenced by specific triggers and individual susceptibilities, in many cases of dermatitis, the compromised skin barrier tends to occur first, creating conditions that facilitate the subsequent inflammatory response. Hence, a compromised skin barrier can lead to increased penetration of irritants and subsequent inflammation, while inflammation can further damage the barrier, creating a vicious cycle. This interplay suggests that both processes are integral to the development of dermatitis and may occur in a closely intertwined sequence. Further, chronic dermatitis is caused by this relationship between a compromised skin barrier and inflammation.