In Part I, we examined the ways in which colloidal oatmeal can be beneficial in the treatment of AD. Colloidal oatmeal has also been found to be of benefit in patients with skin of color and AD. An understanding of how colloidal oatmeal is of benefit in these populations begins with examining the structural and functional distinctions of skin of color.
Patients with skin of color encompass a wide range of racial and ethnic groups, including but not limited to persons of African, African American, Afro-Caribbean, Chinese, Japanese, Native American, Navajo Indian, Southeast Asian, Indian, Middle Eastern, and Latino descent and heritage. Racial and ethnic differences in skin color are directly related to variations in the number, size, and aggregation of melanosomes within the melanocytes and keratinocytes. In subjects with skin of color, there is a trend for melanosomes to be large with greater distribution throughout the epidermis.1 Gunathilake et al demonstrated that dendrites from melanocytes of patients with Fitzpatrick skin type IV–V skin were more acidic than those from type I–II subjects, and that those in type VI–V skin also transfer more melanosomes to the stratum corneum, suggesting that melanosome secretion could contribute to the more acidic pH of type IV–V skin.2 It has been well established that the stratum corneum functions best at a highly acidic surface pH, which is thought to serve an antimicrobial function, regulate barrier homeostasis and desquamation, and allow for optimal activity of the ceramide-generating enzymes sphingomyelinase and β-glucocerebrosidase.2 There are conflictingdata regarding racial differences in the structure of the stratum corneum. In one review article, it is argued that many of the studies cited in the literature have small patient populations and less-than-optimal study designs, which makes it difficult to draw definitive conclusions. In studies using tape-stripping techniques and microscopic visualization, patients with skin types V and VI were shown to have a stratum corneum with increased density but overall equal in thickness to types II and III. Taylor cites various studies, which posit that the increaseddensity may be due to increased lipid content.1
As part of a larger trial comparing the efficacy of colloidal oatmeal with prescription barrier cream in the management of mild to moderate AD, 49 African American children aged 2–15 years were randomly assigned to twice-daily application of either colloidal oatmeal or prescription barrier cream. Colloidal oatmeal provided rapid improvement in baseline EASI score by day 7 (62.9% vs 53.7%) in addition to marked improvement in ratings of itch by day 7 (43.1% vs 33.3%) compared with prescription barrier cream.3 Both treatments were clinically effective and well tolerated.
Clinical Efficacy and Tolerance Beyond Eczema
Colloidal oatmeal has been demonstrated to be effective in several clinical conditions aside from AD. Hand dermatitis is a common and widespread condition that disproportionately effects occupational groups exposed to irritants or allergens. Mainstays of therapy include avoidance of irritants or allergens and use of topical corticosteroids, although long-term use can lead to tachyphylaxis and steroid-sparing agents are