Why Does Folliculitis Decalvans Relapse After Antibiotics?

It is incredibly frustrating when Quinquaud folliculitis decalvans (FD) flares up again after a successful course of antibiotics. Relapse is very common and usually does not mean you did anything wrong. FD is a chronic, scarring inflammatory condition of the hair follicles, not just a simple, temporary infection. While antibiotics can reduce bacteria and calm active inflammation, they often do not eliminate the underlying immune tendency that drives the condition ^[1][2].

Why Relapse Happens

When a flare occurs after stopping antibiotics, it is usually because the underlying drivers of the disease are still active. Several factors can contribute:

• Ongoing Inflammation: Research shows that people with FD have an overactive immune response in their hair follicles, producing excess inflammatory signals ^[3][4]. This immune system overreaction can cause chronic inflammation to return even if bacteria were successfully reduced during treatment.
• The Complex Role of Bacteria: The bacteria Staphylococcus aureus (Staph) is frequently found on the scalp of people with FD, sometimes even in areas that appear completely healthy ^[5]. However, the exact role of these bacteria is still debated—it is not fully settled whether they cause the disease or simply thrive in the inflamed environment. While a relapse might involve persistent bacteria, different strains, or antibiotic resistance ^[6][7], a flare often simply means the underlying inflammation has returned.

Because FD is a chronic condition, it is common for symptoms to return when treatment stops. For example, in one small retrospective study of 28 patients, 80% experienced a relapse after completing a course of the combined antibiotics clindamycin and rifampicin ^[2]. Relapse rates vary, but this highlights that a standard course of antibiotics rarely provides a permanent cure.

What Can Be Done?

If your symptoms have returned, the most important step is to see your dermatologist. Do not simply restart leftover antibiotics or change your dose on your own. Taking antibiotics without supervision can lead to serious risks, including antimicrobial resistance, severe diarrhea, and liver injury ^[2]. Your care team can help you develop a safe, long-term strategy:

• Targeted Testing: If your FD is not responding to standard treatments or if the flare is unusual, your doctor may take a swab of an active pustule (a small pus-filled bump) for a bacterial culture. While a culture cannot guarantee a specific treatment will work, it helps guide medication choices ^[7][8]. Additionally, if overlapping conditions (like lichen planopilaris) are suspected, a small scalp biopsy may be used to help confirm the exact diagnosis ^[9][10].
• Specialist-Directed Maintenance Treatment: Short courses of antibiotics are often not enough for long-term control. The European Academy of Dermatology and Venereology (EADV) suggests that carefully monitored treatment extending beyond the clearing of visible symptoms may be considered by your specialist to help prevent relapse ^[11]. Because prolonged antibiotics carry significant health risks, this requires a customized plan and regular medical monitoring ^[12].
• Exploring Alternative Medications: Depending on your health and the severity of the flare, your doctor might discuss non-antibiotic treatments. Options may include oral isotretinoin, a medication that can offer more durable remission for some patients but requires strict medical monitoring and pregnancy prevention ^[13][2]. For highly active inflammation, a short course of oral corticosteroids (which also carry short- and long-term risks) or other systemic medicines might be used to quickly calm the scalp ^[11].

Next Steps and Expectations

The main goal of any treatment plan for FD is to control the inflammation, relieve symptoms like pain and itching, and prevent further permanent hair loss—not to regrow hair in follicles that have already scarred ^[11].

While waiting for your appointment, you can photograph any new pustules to show your doctor. Seek prompt medical attention if you develop rapidly spreading redness, severe pain, feeling very unwell, or if you experience concerning medication effects such as severe or bloody diarrhea.