Can PRP Cause Alopecia Areata?
No, PRP does not cause alopecia areata (AA); in fact, PRP is an effective and safe treatment option for AA itself, with multiple controlled trials demonstrating increased hair regrowth without triggering or exacerbating autoimmune hair loss. 1, 2
Evidence Supporting PRP Safety in Autoimmune Conditions
The concern about PRP triggering or worsening AA in patients with autoimmune disorders is not supported by clinical evidence:
PRP has been specifically studied in AA patients (an autoimmune condition) and was found to significantly increase hair regrowth compared to both placebo and triamcinolone acetonide injections, with no adverse autoimmune reactions reported. 1
No cases of PRP-induced AA have been documented in the systematic reviews examining PRP use across 621 AA patients and multiple studies in androgenetic alopecia patients. 3, 4
The mechanism of PRP is regenerative, not immunogenic—it works by increasing cell proliferation (measured by Ki-67 markers), enhancing vascularization of perifollicular tissue, and accelerating the telogen-to-anagen transition, without triggering autoimmune responses. 5, 1
Clinical Evidence in AA Patients
A randomized, double-blind, placebo-controlled trial in 45 AA patients demonstrated that PRP significantly increased hair regrowth and decreased hair dystrophy compared to both triamcinolone and placebo, with no side effects noted during the 1-year follow-up period. 1
A 2023 study comparing activated versus non-activated PRP in 40 AA patients confirmed that PRP is safe, effective, and well-tolerated with no reports of disease exacerbation or new autoimmune manifestations. 2
Systematic review of 32 studies (621 AA patients) found PRP had superior or comparable efficacy to intralesional corticosteroids without triggering autoimmune flares or causing AA in previously unaffected patients. 3
Safety Profile Across All Alopecia Types
The only consistent adverse effect is injection-related pain, which is why pharmaceutical-grade topical anesthetic cream is recommended before treatment. 5, 6
No serious adverse events related to PRP injection have been reported across multiple systematic reviews examining both AGA and AA populations. 7, 4
Minimal morbidity and low cost characterize PRP therapy, with high patient satisfaction rates (83% achieving negative hair pull tests in combination therapy). 5, 6
Important Clinical Considerations
PRP is autologous (derived from the patient's own blood), which inherently minimizes the risk of immunogenic reactions or triggering autoimmune responses. 2
Nonactivated PRP is preferred as it demonstrates 31% greater improvement in hair density compared to activated PRP, and activation is not necessary for efficacy in either AGA or AA. 5, 8, 2
The standard protocol involves 3-5 intradermal scalp injection sessions spaced one month apart, using 5-7 mL PRP per session at 2-4 mm depth, with maintenance sessions every 6 months. 5, 6, 8
Bottom Line for Clinical Practice
PRP can be safely used in patients with history of autoimmune disorders, including those with AA itself, without risk of causing or exacerbating autoimmune hair loss. The extensive clinical trial data demonstrates that PRP is not only safe but therapeutically beneficial for AA patients, making concerns about PRP triggering AA unfounded. 1, 2, 3