can sulphur soap cause a rash
These drugs have no relationship to sulfonamide allergy. However sulfhydryl containing drugs can cause unrelated adverse skin reactions such as a rash or pemphigus (a rare autoimmune blistering disease). Sulfates are also commonly found in soaps and cosmetics; allergies to sulfates are extremely rare. Sulfites are chemicals used as preservatives in food and drugs, e.g. sulfur dioxide and sodium sulfite. Allergy to sulfite preservatives can cause anaphylaxis, other rashes, asthma, seizures and death. People with asthma are at higher risk of sulfite allergy.