A reader wrote:
Please could you write further on Allergic Contact Dermatitis and the microbiome? I am convinced there is a clear connection there, and note one article you reference above specifically supporting the same also. Would be very interested in your holistic take on the same, as you have done with POTS and MCAS.
My approach is always to try to keep to the gold standard, studies on PubMed.
- The role of skin and gut microbiome and epigenetic modifications upon skin autoimmune disorders 
” The aim of this review article is to shed new light on some of the commonest skin disorders such as psoriasis, atopic dermatitis, allergic contact dermatitis, with special regards to epigenetic pathogenetic mechanisms such as miRNAs expression and skin and gut microbiome alterations.”
- The gut microbiome alterations in allergic and inflammatory skin diseases – an update 
“The gut microbiome alterations are linked to the pathogenesis of the allergic, cardiovascular, gastrointestinal, metabolic, neurodevelopmental, psychiatric and neurodegenerative diseases and cancer. Moreover, there is increasing evidence connecting the skin condition with the gastrointestinal microbiome, which has been described as the skin-gut axis.”
- Bacterial Dysbiosis and Translocation in Psoriasis Vulgaris 
” Alterations in the gut microbiome have been characterized by a decrease in the Bacteroidetes phylum and an increase in the Faecalibacterium genus… The abundance of Faecalibacterium praunitzii was reduced to a greater extent in patients with both IBD and psoriasis, when compared to patients with only one of the conditions…IBD has been associated with psoriasis since the 1970s (Verbov, 1973; Yates et al., 1982; Lee et al., 1990). However, this association has largely been disregarded. [Also applies to UC and Crohn’s Disease]”
- Inhibitory effects of dietary soy isoflavone and gut microbiota on contact hypersensitivity in mice  ” often used as a mouse model for allergic contact dermatitis (ACD);”
- “Constipation was an associated factor for development of atopic dermatitis (AD) (1.17) and AR (1.17), regular intake of lactic acid bacteria was not an associated factor for development of allergic diseases but was a factor for remission of AD (1.22)” 
At first look, it looks like medical professionals dealing with Allergic Contact Dermatitis and similar conditions, do not want to deal with the gut microbiome. I call this the “It’s not in my wheelhouse” or “I want to keep into my thin silo” syndrome. There is a nasty situation created by excessive specialization of medicine and medical research.
I hate to say it, but the fastest way forward (and to get relief) may be doing citizen science via https://microbiomeprescription.com/ This depends on people with Allergic Contact Dermatitis getting appropriate 16s tests (see suitable providers here as well as which ones are most popular here). The site will automatically show relationships once we get 20 or more annotated samples uploaded.
I have added these to the symptom list on the site.
- Official Diagnosis: Allergic Contact Dermatitis
- Official Diagnosis: Dermatitis (all types)