Injury enhances TLR2 function and antimicrobial peptide expression through a vitamin D-dependent mechanism.

An essential element of the innate immune response to injury is the capacity to recognize microbial invasion and stimulate production of antimicrobial peptides. We investigated how this process is controlled in the epidermis. Keratinocytes surrounding a wound increased expression of the genes coding for the microbial pattern recognition receptors CD14 and TLR2, complementing an increase in cathelicidin antimicrobial peptide expression. These genes were induced by 1,25(OH)2 vitamin D3 (1,25D3; its active form), suggesting a role for vitamin D3 in this process. How 1,25D3 could participate in the injury response was explained by findings that the levels of CYP27B1, which converts 25OH vitamin D3 (25D3) to active 1,25D3, were increased in wounds and induced in keratinocytes in response to TGF-beta1. Blocking the vitamin D receptor, inhibiting CYP27B1, or limiting 25D3 availability prevented TGF-beta1 from inducing cathelicidin, CD14, or TLR2 in human keratinocytes, while CYP27B1-deficient mice failed to increase CD14 expression following wounding. The functional consequence of these observations was confirmed by demonstrating that 1,25D3 enabled keratinocytes to recognize microbial components through TLR2 and respond by cathelicidin production. Thus, we demonstrate what we believe to be a previously unexpected role for vitamin D3 in innate immunity, enabling keratinocytes to recognize and respond to microbes and to protect wounds against infection.

White piedra in children.

BACKGROUND: White piedra is a fungal infection of the hair shaft caused by species of Trichosporon. Rarely has this infection been reported in the United States. Historically, infected individuals required shaving of their hair to achieve clearance of the infection. OBJECTIVE: We sought to describe 8 cases of Trichosporon scalp infections seen in the northeastern United States. METHODS: We conducted chart review and prospective evaluation of 7 girls and 1 boy seen in two dermatology practices in New Haven, Conn, and New York, NY. RESULTS: Seven girls, ages 4 to 16 years old, and one 4-year-old boy were determined to have Trichosporon scalp infection, all through culture. Of the 8 children who were available for follow-up, 7 had clearance of their infection with a combination of oral azole antifungal medication and azole antifungal shampoo, without shaving the scalp hair. LIMITATIONS: This was a sample of patients from a localized region of the United States. CONCLUSIONS: White piedra is emerging as a commonly seen hair and scalp infection in the northeastern United States. Contrary to prior publications, scalp and hair infection may be successfully treated with a combination of oral azole antifungals and shampoos without shaving the scalp.

Atopic dermatitis in children, part 1: epidemiology, clinical features, and complications.

Atopic dermatitis (AD), also known as eczema, is a chronic skin condition, characterized by itch (pruritus) and dryness (xerosis). AD lesions appear as pruritic red plaques that ooze when scratched. Children with AD are excessively sensitive to irritants such as scented products and dust due to their impaired skin barrier and skin immune responses. AD is among the most common disorders of childhood and its incidence is increasing. AD is an all-encompassing disease that causes sleep disturbances in the affected child, disrupting the entire household. Patients with AD also are prone to bacterial overgrowth, impetigo, and extensive viral infections. Consequently, familiarity with the most recent literature is of utmost importance so that dermatologists and pediatricians can appropriately manage their patients.

Atopic dermatitis in children, part 2: treatment options.

Treatment options for children with atopic dermatitis (AD) include environmental modifications, corticosteroids, calcineurin inhibitors, and some less frequently used alternative therapies. Treatment of AD is a multifaceted approach that requires avoidance of specific triggers and irritants, repair and maintenance of the stratum corneum, cessation of the itch-scratch cycle, and reduction of inflammation.

Contact dermatitis to botanical extracts.

A review of the literature of reported cases of contact dermatitis to a variety of natural herbal extracts is Presented. Natural extracts are commonly used ingredients in many cosmetic preparations and homeopathic remedies. Although the term natural botanical extracts inherently purports to have beneficial and benign properties, these extracts can cause adverse reactions in individuals. As such, dermatologists should be cognizant of these agents as possible sources of allergenicity in patients presenting with contact dermatitis.