Folliculitis decalvans is an inflammatory scalp condition that can cause permanent scarring hair loss. Painful crusting, pus-filled spots, groups of hairs emerging together or an enlarging patch should be assessed before booking hair-growth injections. Controlling the inflammation and protecting remaining follicles takes priority over a cosmetic treatment plan.
This is different from ordinary pattern thinning. A consultation that identifies that difference can save time and help you reach the right treatment pathway rather than repeating a course aimed at the wrong problem.
What is folliculitis decalvans?
The British Association of Dermatologists describes folliculitis decalvans as a rare, long-term condition in which inflammation around hair roots leads to scarring. The scalp is the usual site, although other hair-bearing areas can occasionally be affected. It is not a type of skin cancer and is not generally considered contagious.
The cause is not fully understood. A reaction involving Staphylococcus aureus, a bacterium found on healthy skin, may have a role. Finding bacteria does not turn this into a simple contagious infection or mean that a shampoo alone will settle it.
A characteristic feature is tufting, where several hairs appear to grow together from the same opening. The surrounding skin may be red, swollen, scaly or crusted. Pustules can occur, and patches of permanent loss may enlarge. Some people have discomfort; others have little, so absence of pain does not establish that the condition is inactive.
Arrange a scalp assessment before choosing injections.
How is this different from ordinary scalp spots?
A single scalp spot does not diagnose folliculitis decalvans. Other conditions can cause inflammation, itching or patchy loss, including fungal infection. The pattern, examination and course over time matter. A clinician may need to examine follicle openings closely rather than decide from a photograph alone.
Our guide to scalp folliculitis and hair loss covers the broader problem of scalp spots. Folliculitis decalvans is a more specific scarring condition, which is why an expanding patch, tufting and persistent crusting deserve a separate assessment.
Tell the clinician how long the problem has been present, whether it comes and goes and which products or treatments you have tried. Bring photographs taken over time and the names of any medicines. Do not assume that a previous label of dandruff explains a changing patch.
What might happen at the assessment?
A dermatologist may recognise the condition by examination and use a magnifying device to inspect follicles. The BAD leaflet describes taking a swab in some cases and checking for fungal infection when relevant. A small skin biopsy may help when the diagnosis needs confirmation.
Not everyone needs every test. The purpose is to establish whether inflammation is active, whether scarring has occurred and what treatment is appropriate. A useful plan makes clear who is managing the condition and how response will be reviewed.
Ask whether the diagnosis is secure, what signs will indicate improvement and which changes should prompt earlier contact. Explain whether the condition affects sleep, comfort, confidence or your ability to manage hair normally. Those effects matter even when the affected area looks small.
Where does PRP fit?
PRP is not an established first-line treatment for folliculitis decalvans in the BAD patient guidance. Its role in selected pattern hair loss cannot be transferred to a disease that destroys follicles through inflammation. A claim that growth factors will regenerate a scarred patch would go beyond the evidence used for this guide.
The London PRP Clinic's published services include doctor-led hair PRP. That is not a promise that PRP is suitable for every hair-loss diagnosis or that this clinic provides every specialist treatment described in a dermatology leaflet. Suitability and any referral need should be discussed before a course is booked.
When two problems coexist, such as pattern thinning away from an inflammatory patch, the clinician needs to separate them. A possible treatment for one area is not a treatment for the other. Protecting your scalp and agreeing a coherent plan comes before adding procedures.
Discuss the diagnosis and the right next step.
Can the lost hair grow back?
The BAD leaflet explains that scarring hair loss is permanent. The aim of medical care is therefore to control disease and prevent further loss, rather than promise that destroyed follicles can be restored. Some visible thinning may also reflect inflammation around surviving follicles, but an individual prognosis requires examination.
Treatment may involve anti-inflammatory approaches and prescription medicines under specialist care. This article does not provide a medicine schedule. Do not start, stop or repeat antibiotics or other prescription treatment on the basis of an online description.
A practical review plan should cover the active edge of the patch as well as its centre. Photographs taken under similar lighting can help document change, but they do not replace checking for inflammation. Ask what success means for your case, including symptom control and stability, not only density.
When should I seek help sooner?
Arrange prompt assessment for a patch that is enlarging, recurrent discharge, persistent pain or signs of scarring. If you develop rapidly worsening swelling, fever or feel unwell, seek urgent clinical advice rather than using a routine cosmetic enquiry route.
Until you are assessed, avoid picking crusts or repeatedly trying new procedures on irritated skin. Keep a list of what has been applied and share it at the consultation. A clear account of changes is more useful than concealing symptoms immediately before a visit.
Evidence and sources
British Association of Dermatologists, Folliculitis decalvans supports the description, diagnostic options, scarring risk and treatment context. The leaflet is dated November 2022 and was checked 4 November 2026. PRP is not presented here as proven treatment for this condition. This is general information and cannot diagnose a scalp patch.
Request an assessment of inflamed scalp and patchy hair loss.