Lymphokines and cytokines released by T lymphocytes and other immune cells represent the most important stimuli that elicit the inflammatory activation of keratinocytes. Depending on the type and extent of T-cell infiltrate present in allergic contact dermatitis and atopic dermatitis skin lesions, keratinocytes are exposed to different cytokine micromilieu and, in turn, produce flogosis mediators qualitatively and quantitatively specific for each disease. Keratinocyte-derived inflammatory molecules amplificate skin immune responses associated with allergic contact dermatitis and atopic dermatitis, and contribute to the disease process and clinical phenotype development.