Sodium Metabisulfite is generally a lower-concern formula helper for seborrheic dermatitis, but people with a known sulfite contact allergy may need to avoid it. It protects formulas from oxidation or spoilage rather than treating seb derm.

Patch-test studies show that contact allergy occurs in a minority of selected dermatitis patients, especially around the face or hands. That is an allergy consideration, not proof of a seb derm trigger. If a product repeatedly causes itching, swelling or a new rash, stop using it and seek professional advice.