DCP (diphenylcyclopropenone) treatment

DCP (diphenylcyclopropenone) is a treatment for alopecia areata (patchy hair loss) and stubborn warts. It works by causing a mild allergic reaction in the skin. This reaction redirects the immune system, which can help hair regrow or warts clear.

How treatment works

1. Sensitisation: at your first visit, a small amount of strong DCP is applied to a small area of skin, often the inner arm or the scalp. This “teaches” your immune system to react to it.
2. Treatment: about 2 weeks later, a weak solution is painted on the area being treated. This is repeated every week. The strength is slowly increased until you get a mild reaction.
3. Treatment usually continues for several months. Hair regrowth often takes 3 months or more to appear.

After each application

• Keep the area covered and out of light for 48 hours. DCP is broken down by light. For the scalp, wear a hat or scarf when outdoors.
• Do not wash the area for 48 hours, then wash it off with soap and water.
• Wash your hands if you touch the area, and keep it away from other people, especially children.

What is a normal reaction?

A mild reaction over 24 to 48 hours is the goal:

• Mild itch
• Redness
• Some flaking or scaling

When the reaction is too strong

Wash the area well with soap and water and contact the clinic if you have:

• Blistering or weeping
• Marked swelling, especially around the eyes
• A rash spreading beyond the treated area
• Swollen, tender lymph glands in the neck, or a fever

We may lower the strength for your next treatment. A steroid cream can help settle a strong reaction. Use it only as we have directed.

Other things to know

• The treated skin can become darker or lighter in patches, especially in darker skin types.
• DCP is not used during pregnancy. Please tell us if you are pregnant or planning a pregnancy.