How Do Doctors Assess Folliculitis Decalvans Activity?

Doctors determine whether Quinquaud folliculitis decalvans (FD) is active by looking for current signs of inflammation and checking if the hair loss is spreading ^[1][2]. Because FD is a scarring condition, it is common to worry that the disease is still active simply because you have smooth, hairless spots. However, hair loss is permanent where the follicles have been completely destroyed, meaning these hairless areas will remain even after the inflammation has stopped ^[3][4]. A quiet, stable scarred area without redness, pain, or new bumps suggests the condition may be inactive, but your dermatologist will monitor you over time to be sure ^[2][5].

Signs That Suggest Active Inflammation

FD is an inflammatory condition that damages hair follicles. While bacteria like Staphylococcus aureus are sometimes found in these areas, their presence does not definitively prove they are the sole cause of the disease ^[6]. When the disease is active, your doctor will look for:

• Visible inflammation: New pus-filled bumps (pustules), crusts, sores, or discharge are classic signs of a flare ^[7][8].
• Redness and scale: Even mild active FD can cause redness (erythema) and scaling (hyperkeratosis) around the hair follicles, without any pustules ^[7].
• Symptoms: Worsening scalp pain, tenderness, burning, or itchiness can be clues that inflammation has returned ^[1][9]. However, some active disease can be subtle or asymptomatic.
• Spreading hair loss: If the bald patches are demonstrably getting larger, the disease is likely still active ^[1][5].
• New tufting: “Tufted hairs” (several hairs growing out of a single opening) are a characteristic consequence of scarring ^[10]. While tufts can remain as an old feature of scarring, newly appearing tufting at the edges of a patch can be a clue to ongoing damage ^[10].

Signs That Suggest the Disease Is Inactive (Remission)

Doctors generally consider FD to be in remission when there is a lack of inflammatory activity and the disease is stable ^[2][5]. This typically means:

• No new pustules, crusts, or redness ^[2].
• No significant pain, itching, or burning ^[5].
• The size of the hairless patch is not changing over time ^[2].
• Old scarring: The affected skin may look white, shiny, and completely smooth. Because the hair follicles have been destroyed, hair will not regrow here ^[3]. However, this lack of hair simply indicates prior damage, not necessarily current activity ^[2].

Remission is judged over time by your clinician, and it is important to remember that FD can relapse after a quiet period.

How Doctors Evaluate Your Scalp

To tell the difference between old scars and active disease, dermatologists use several complementary tools:

• Trichoscopy: Doctors use a handheld magnifying device to look closely at your scalp. Trichoscopy can reveal hidden redness, tiny pustules, and abnormal blood vessels if the disease is active ^[10][11]. It can also document scarring by showing a lack of follicular openings (pores) ^[4]. However, no single trichoscopic sign independently proves activity or remission.
• Serial Photographs: Taking standardized photos of your scalp helps objectively measure whether the hairless patches are expanding ^[11]. You can also track this at home by taking photos of the same areas with consistent lighting, parting, and camera distance to share with your doctor.
• Bacterial Culture: If you have persistent, recurrent, or unusually purulent lesions, your doctor may swab them ^[6]. While this identifies bacteria, a positive result must be interpreted alongside your symptoms to help guide your treatment plan ^[12].
• Scalp Biopsy: If it is difficult to tell if inflammation is still happening, a small skin sample can be examined under a microscope ^[13]. Because a biopsy only samples a small area, your dermatologist will carefully choose the site and interpret the results alongside your clinical picture ^[14].

When to Contact Your Doctor Early

Do not wait for your next scheduled appointment if you notice signs that the disease is waking up. Contact your doctor earlier if you develop new painful bumps, spreading redness, increased tenderness, or if you feel your hairless patch is actively getting larger. Catching a flare-up early may reduce the risk of further permanent hair loss ^[3].

Seek urgent medical care if you experience rapidly spreading warmth and redness, severe pain, fever, facial swelling, or significant drainage, as these could indicate a more serious secondary skin infection rather than routine FD activity.