The effect of UVB radiation on skin microbiota in patients with atopic dermatitis and healthy controls

Abstract

Objectives. To investigate Staphylococcus aureus and Staphylococcus epidermidis quantitatively in adult patients with atopic dermatitis and in healthy controls treated with UVB radiation. Study design. Twenty-three adult patients (of these, 3 were excluded) with flexural atopic dermatitis and 20 healthy controls were randomly selected at the outpatient clinic of the Dermatological Department, University Hospital, North Norway. Methods. Adult patients with atopic dermatitis (n=20) and healthy controls (n=20) were given 20 UVB treatments. Bacterial samples were collected before treatment, after 4 weeks of treatment, and finally after 2 weeks follow-up. Results. The main bacteria found were Staphylococcus aureus and Staphylococcus epidermidis. 16 of the 20 patients with atopic dermatitis had Staphylococcus aureus in lesional skin and 12 in non-lesional skin. None of the healthy controls had Staphylococcus aureus in the sample from the flexural elbow. The Staphylococcus aureus counts decreased (not significant) in lesional skin after 4 weeks of treatment and Staphylococcus aureus counts were slightly higher after 2 weeks follow up. The same figures were also seen in non-lesional skin and forehead. Conclusions. Staphylococcus aureus is widely colonised in the skin of atopic dermatitis patients, but is rare in healthy adults. UVB treatment decreases the Staphylococcus aureus count in patients with atopic dermatitis. (Int J Circumpolar Health 2008; 67(2-3):254-260)

Consensus‐based European guidelines for treatment of atopic eczema (atopic dermatitis) in adults and children: part I

“…The known mechanisms of action target immunomodulation through apoptosis of inflammatory cells, inhibition of Langerhans cells and alteration of cytokine production . In addition, UV has an antimicrobial effect reducing the colonization of S. aureus, due to its anti‐inflammatory effect and improves skin barrier . A different explanation could be supported by the role of Vitamin D: a recent study demonstrated that a 2‐week course of heliotherapy significantly improved vitamin D balance by increasing serum calcidiol concentration and caused a marked healing of AE .…”

ETFAD/EADV Eczema task force 2015 position paper on diagnosis and treatment of atopic dermatitis in adult and paediatric patients

“…Photo(chemo)therapy is a good therapeutic option to improve skin lesions, pruritus and sleeplessness in AD patients, with remission periods up to 6 months and no documented serious short‐term side‐effects . Phototherapy for AD might work due to several factors like the suppression of the antigen‐presenting function of the Langerhans’ cells, induction of antimicrobial peptides, the induction of apoptosis in infiltrating T cells, a reduction of the colonization by Staphylococcus aureus and Malassezia sp . and there may be a reduced antigen presentation by an increased phototherapy‐induced thickness of the stratum corneum leading to a milder AD …”

Skin microbiota: Microbial community structure and its potential association with health and disease

“…Seasonality has been demonstrated in influencing diseases of the skin, likely as a result of microbiota alterations in response to climate changes (Jha and Gurung, 2006). Moreover, ultraviolet B (UVB) radiation, known to impact skin conditions, was observed to have disparate microbicidal effects on the skin microbiota (Dotterud et al, 2008). In particular, S. aureus appeared to be more sensitive to the radiation treatment than S. epidermidis .…”