In short
Resorcinol is a chemical substance used on the skin as an antiseptic and external analgesic. It is a common ingredient in over-the-counter creams for itching and in hair dyes, and it is now being studied in a Phase 3 clinical trial as part of a treatment plan for hidradenitis suppurativa (HS), a painful skin condition. The trial includes 100 participants and compares a standard treatment with a biologic medicine plus a topical cream containing resorcinol.
Key points
- Resorcinol is an antiseptic and external analgesic used on the skin.
- It is being studied in a Phase 3 trial for hidradenitis suppurativa.
- The trial has 100 participants and lasts about two years.
- Resorcinol is given as a topical cream in the study.
- The trial compares adalimumab with standard of care (doxycycline).
- The main goal is to see which treatment better prevents severe disease.
What is resorcinol?
Resorcinol is a chemical substance that is used on the skin. It works as an antiseptic and as an external analgesic, which means it can help relieve pain or itching on the surface of the skin. In the United States, resorcinol is available over the counter in a cream that also contains benzocaine, another external analgesic. Resorcinol is also used in cosmetics, including oxidative hair dyes, hair lotions and shampoos. In the clinical trial included here, resorcinol is used as a topical treatment, which means it is applied directly to the skin.
How does resorcinol work?
Resorcinol acts on the surface of the skin. It is classified as an external analgesic, meaning it helps reduce discomfort at the site where it is applied. The product information for an over-the-counter cream states that resorcinol is used to temporarily relieve itching. In the context of hidradenitis suppurativa, the trial uses resorcinol as a topical agent, but the registry record does not describe a specific molecular target for this substance.
Which conditions is resorcinol used or studied for?
- Hidradenitis suppurativa — a long-term skin condition that causes painful lumps, abscesses and tunnels under the skin. Resorcinol is used as a topical treatment in a Phase 3 trial for this condition.
- Itching — resorcinol is an ingredient in over-the-counter creams that temporarily relieve itching.
How is resorcinol given?
Resorcinol is applied to the skin. In the clinical trial, it is given as a topical preparation, meaning a product that is put directly on the affected area. Over-the-counter products contain resorcinol in creams, and cosmetic products use it in hair lotions and shampoos. The dose used in the trial is reported as 0.41 grams.
What do the clinical trials show?
One clinical trial involving resorcinol is included in this page. It is a Phase 3 interventional study that includes 100 participants with hidradenitis suppurativa. The trial is authorised, meaning it has received approval to proceed. The study compares two treatment approaches: adalimumab, a biologic medicine given by subcutaneous injection, and standard of care with doxycycline, an oral antibiotic. Resorcinol is given as a topical treatment in this trial.
The main outcome measured is the development of severe hidradenitis suppurativa over a two-year period. Severe disease is defined as either Hurley stage 3, which means multiple interconnected tunnels and nodules throughout the affected area, or an IHS4 score of 11 points or more. The trial looks at the percentage of people with non-severe disease at the start who progress to severe disease by week 104.
The study focuses on adults with non-severe hidradenitis suppurativa who are at high risk of progression to severe disease. The research question is whether adalimumab, compared with standard of care, reduces the proportion of people who progress to severe disease over 104 weeks.
What side effects are known?
According to the European Commission's Scientific Committee on Consumer Safety (SCCS), resorcinol is a moderate skin sensitiser based on data from animal studies. Clinical studies show that the frequency of contact sensitisation in humans is low. The SCCS also assessed resorcinol for potential endocrine disrupting properties and concluded that it is safe when used as an oxidative hair dye in products intended for hair and eyelashes up to 1.25% and up to 0.5% in hair lotions and shampoos. The over-the-counter product label advises avoiding contact with the eyes and rinsing thoroughly with water if contact occurs.