I. Introduction

Topical medications, or topicals, are medicines applied to the skin. They come in creams, washes, ointments, gels, foams, sprays, and others. Topicals are often used to treat skin diseases since they are easy to use and relatively safe, though all topical medications have the potential to cause skin irritation or allergic reactions in some people.

Topicals are often prescribed for patients with mild HS. For patients with moderate to severe HS, topicals are typically recommended in combination with other treatments, such as oral or injectable medications

There are five kinds of topical medications used to treat HS symptoms: antibiotics, antiseptics, keratolytics, bathing regimens, and complementary and alternative treatments.

II. Topical Antibiotics

There are bacteria, or germs, living on our skin and in our hair follicles all the time. Some bacteria do not cause any problems for us, while others can cause disease. Even though HS is not an infection, bacteria can play a role in the disease. Antibiotics are medications that kill bacteria by preventing the bacteria from doing specific activities. For example, antibiotics can damage the protective casing of bacteria, prevent the formation of the protective casing, or prevent bacteria from dividing and spreading. Each antibiotic works on certain types of bacteria. Antibiotics can also help in other ways, such as by reducing inflammation. Bacteria can find ways to survive antibiotics, called antibiotic resistance, if the antibiotic is used alone for a long time. To avoid this problem, antibiotics can be used for less than twelve weeks, or they can be combined with antiseptics, like benzoyl peroxide wash. Topical antibiotics alone are only helpful for very mild cases of HS. Most people need additional treatments.

Topical Clindamycin. Topical clindamycin has been proven to treat HS in more than one study. For patients with mild HS, topical clindamycin can work similarly to the oral antibiotic tetracycline. It works well to treat HS bumps near the surface of the skin, but does not work as well for tunnels, abscesses, or nodules that are deeper in the skin and seen in patients with more severe disease. Topical clindamycin comes as a lotion or liquid solution. It is usually applied twice a day to the areas of the skin affected by HS and allowed time to soak in.

Topical Fusidic Acid. Topical fusidic acid comes as an ointment or cream. The 2% strength ointment helped heal HS lesions in one study when it was used three times a day for four weeks. More studies would help us better understand how useful it can be for patients with HS.

Topical Dapsone. Topical dapsone can sometimes help patients with HS, but it has not been well studied. Topical dapsone comes in a 5% and 7.5% gel. Topical Gentamicin.

Topical gentamicin has been studied in post-surgery HS patients. It helped the wounds heal and prevented infections, but it did not help prevent HS from coming back in the surgery areas. Topical gentamicin comes as a cream or ointment.

III. Topical Antiseptics

Like antibiotics, antiseptics also kill bacteria. For example, antiseptics can break the outer coating or protective casing of bacteria, causing the bacteria to die. Bacteria cannot find ways to survive antiseptics, so there is very little risk of bacterial resistance with the use of topical antiseptics. This is why using antiseptics in addition to antibiotics can be helpful. The antiseptics can kill any bacteria that are finding ways to survive the antibiotics.

Antiseptic washes are recommended to nearly all patients treating their HS. They are used to wash the areas affected by HS when bathing. Antiseptic washes work best if they are left on the skin for a few minutes before rinsed off. They do not need to be used on areas of the body not affected by HS. Many antiseptic washes can cause skin dryness, so some people with HS find it helpful to also use a moisturizer.

Chlorhexidine Wash. Though there have not been any published studies to prove that chlorhexidine wash helps with HS symptoms, healthcare providers and patients with HS have found it beneficial. Chlorhexidine is available over-the counter. It can cause skin irritation or an allergic rash, but that is rare.

Topical Benzoyl Peroxide and Wash. Benzoyl peroxide is available over-the-counter as a wash, gel, lotion, or cream in strengths from 2.5% to 10%. For patients with HS, the wash is typically the option used. Though it is primarily an antiseptic, benzoyl peroxide also has a keratolytic effect (please see “topical keratolytics” section below).

Topical Zinc Pyrithione and Wash. Zinc pyrithione is available over-the-counter as a spray, shampoo, or soap. It can kill yeast that grows on the skin. There are currently no published studies to prove that it can work to treat HS, but some healthcare providers report that it works as well as chlorhexidine.

Topical Ammonium Bituminosulfate (Ichthammol). Topical ichthammol is recommended by some experts, especially in Europe. There are no published studies to prove that it works. Ichthammol is available over-the-counter and the strength of topical ichthammol used by some people with HS is the 10% ointment. It can cause skin irritation, stain fabrics, and has a foul odor.

IV. Topical Keratolytics

Studies have shown that HS can block the openings where hairs grow out of the skin, called the hair follicles. This traps bacteria and oil in the hair follicle, which leads to the skin changes seen in people with HS. Keratolytics are medications that help the dead skin cells on top of the skin peel off, which helps prevent the blockage of hair follicles.

Topical Resorcinol. Resorcinol is only available from specialty compounding pharmacies in the United States. Studies have shown that resorcinol can help decrease pain from HS and make HS lesions heal more quickly, with 80% of abscesses healing within a month. It does not help the scars and tunnels caused by HS though. The strength of topical resorcinol prescribed for people with HS is usually around 15% but can range from 10-30%. It is applied once or twice daily. Potential side effects include skin irritation, peeling, and darkening. It should not be used on open wounds or used by pregnant women.

Topical Azelaic Acid. Some healthcare providers find azelaic acid helpful for people with HS, especially children, but there are no published studies on its use. It is available as a gel, cream, or foam that is applied once or twice daily. Topical azelaic acid can cause skin dryness, irritation, allergic rash, and sun sensitivity.

V. Bathing Regimens

Bathing regimens can help by reducing inflammation, pain, and itching. While formal studies have not been conducted on bathing regimens, patients with HS have reported benefits from bleach baths and Epsom salt baths. Bleach (sodium hypochlorite) is well-known to kill bacteria on surfaces when used at a high concentration. Studies have shown that bleach baths work not by killing bacteria but instead by reducing skin inflammation, itching, and pain. Epsom salt, also known as magnesium sulfate, can help relieve skin and muscle problems. We think the magnesium and sulfate are absorbed into the skin to relieve pain nerves and relax muscles. Please see Chapter 14 for more details on bathing regimens.

VI. Complementary and Alternative Topical Treatment

Complementary and alternative treatments are not standard medicines used to treat disease, and they usually do not have as many, or any, studies to support their benefit. They are often used with traditional medicines, especially for difficult diseases like HS, where traditional medicines often are not enough to bring relief. Examples of complementary and alternative topicals that patients have reported using include topical cannabidiol (CBD) oil and topical turmeric. Keep in mind that these complementary and alternative topical treatments should not be applied directly to open wounds unless directed.

Topical Cannabidiol. CBD is a chemical that is found in marijuana and hemp plants. It does not cause people to feel “high,” a different chemical called tetrahydrocannabinol (THC) is responsible for that feeling. CBD oil or cream may help with wound healing and reducing pain when used as a topical. There are no published studies on topical CBD use for patients with HS, but a survey of people with HS found that it is a commonly used complementary treatment and many feel it can be helpful. There is no regulation over the purity or dosage of over-the-counter CBD products as none of them have been FDA-approved.

Topical Turmeric. Turmeric is used as a spice in cooking (the active ingredient is called curcumin). It has been used as a medicine in many parts of the world for hundreds of years. There are no studies to show that turmeric can help treat HS when applied to the skin, but some patients have found it helpful.