A randomized controlled pilot study comparing the efficacy of topical coal tar to topical corticosteroids in children aged 1 to < 16 years with moderate-severe atopic dermatitis.

Atopic dermatitis (AD) is an inflammatory skin disease, occurring most
frequently in children. Currently, topically applied corticosteroids are used
as a standard anti-inflammatory treatment. When a corticosteroid with a high
potency is used for a long period of time adverse effects like skin atrophy and
systemic effects may occur, especially in children. In addition, corticophobia
among patients is an issue that warrants alternatives for the treatment of AD
in children. An alternative treatment is the topical application of coal tar,
which is known to be an effective and safe treatment for AD for ages, and is
used in our department for decennia. Although there is convincing evidence in
the literature on the safety of coal tar, evidence in the literature on the
efficacy of coal tar in the treatment of AD is lacking, especially in children.
Research is needed to provide evidence for guidelines for topical treatment
with coal tar in children.

To evaluate efficacy of topical treatment with coal tar compared to topical
treatment with corticosteroids in children aged 1 to <16 years with moderate to
severe AD, based on the percentage change in Eczema Area and Severity Index
(EASI) at week 2. Secondary outcomes: percentage change in EASI at week 4, the
proportion of patients with EASI-75 at week 2 and week 4, decrease in VAS score
for pruritus, changes in patient-reported outcome (POEM and Patient PGA),
changes in quality of life (CDLQI), changes in family impact (DFI) and
tolerability of both treatments. In addition, we aim to investigate a possible
association between a filaggrin (FLG) genotype and efficacy of topical coal
tar, and to evaluate changes in Natural Moisturizing Factors (NMF) in the
stratum corneum and changes in skin microbiota between patients treated with
topical coal tar and topical corticosteroids.

We aim to conduct an investigator-initiated, parallel-group randomized
controlled pilot study comparing the topical application of coal tar to
moderate-potency topical corticosteroids.

Patients will be randomized in two groups: (1) topical treatment with coal tar
or (2) topical treatment with moderate potency corticosteroids for a treatment
duration of 4 weeks. After 2 weeks, there is a rescue medication option
consisting of additional topical treatment with either corticosteroids or coal
tar, depending on the treatment arm.

Both treatments used in this trial, are normally used in daily clinical
practice. In fact, the only difference between daily clinical practice and this
trail, is the randomization of the children in two arms. In addition to the
daily clinical practice, the children and their parents will have to fill out
questionnaires, which will take a little extra time. In addition, saliva will
be collected for DNA isolation, dead cornified cells will be collected for NMF
analysis by application of adhesive tapes, and swaps will be taken from the
skin for microbiome analysis. These procedures are not painful or frightening
for the children. There are no risks associated with participation.