TABLE 3.

Studies using PRP for alopecia areata treatment

STUDY DESIGN	STUDY GROUPS	PRP PREPARATION	OUTCOMES
Trink et al33
•Randomized, double-blind, placebo- and active-controlled, half-head, parallel-group study •45 AA patients with chronic, recurring disease of at least 2 years’ duration, and having between four and six symmetrically distributed patches of hair loss	3 injections at 1-month intervals: 1.PRP 2.TrA: 2.5 mg/mL 3.Distilled water	1.36 mL of peripheral blood 2.Centrifuged at 70 × g for 8 min 3.The PRP fraction was separated and suspended in calcium gluconate. 4.Platelet concentration: 3.5×	At 1 year poststudy: •Complete remission rate: PRP (60%) > TrA (27%) •Regrowth of fully pigmented hair: PRP (96%) > TrA (25%) •Relapse rate: PRP (31%) < TrA (71%) •The number of dystrophic hairs by dermoscopic photomicrographs decrease •Burning or itching sensation decrease •Ki-67 increase
Albalat et al34
•Randomized double-blind study •80 patients	3 to 5 subfollicular injections at 2-week intervals 1.PRP 2.TrA: 5 mg/mL	1.15mL of venous blood was collected in five special 3mL sterile tubes containing an anticoagulant (sodium citrate 3.8%). 2.1st spin: 150 × g for 10 min 3.2nd spin 1500 to 2000 × g for 10 min 4.Activator: calcium chloride (0.1 mL of CaCl2 per 0.9mL of PRP 5.3mL of PRP in total	•Hair regrowth with improvement: PRP = TrA •Relapse rate: PRP (5%) < TrA (25%) at 6 months after treatment
Shumez et al35
•Nonrandomized controlled study •74 patients (48 TrA, 26 PRP)	3 injections at 3-week intervals: 1.PRP 2.TrA: 10mg/mL	1.20 mL of blood was drawn 2.1st spin: 5,000 rpm for 15 min 3.2nd spin: 2000 rpm for 5–10 min 4.Activator: 10% calcium chloride (0.3 mL per 1 mL of PRP)	•Overall improvement: PRP = TrA (100% in the 9th week and on the 3rd month for all patients)
Singh et al36
•Prospective study •20 patients with longer than 2-year duration	•6 subfollicular PRP injections at 4-week intervals	•25mL of blood was drawn and the PRP solution obtained from the lab was used within 30 min of its preparation	•Only one patient had a relapse at the end of 1 year
Donovan et al37
•Case report •Ophiasis-type AA with corticosteroid-resistant and bipolar disorder	•PRP injection	1.Arthrex Angel System (Arthrex Inc., Naples, FL) at a concentration 3.5 times above baseline using a 2% hematocrit setting 2.120mL of blood was drawn	•Hair regrowth was noted by 1 month with robust regrowth of hairs measuring 2.8cm by 3 months
Thamer Mubki38
•Case report •A patient with chronic diffuse AA for more than 5 years	•Right half of scalp: 4 PRP injections alternated with 4 TrA injection at 2-week intervals •Left half of scalp: 4 TrA injections at 4-week intervals; TrA (2.5 mg/mL, total of 4mL); PRP (2–3mL)	1.Pure PRP System, Seoul, Korea) containing ACD-A (trisodium citrate, citric acid, and dextrose) 2.18mL of blood was drawn 3.centrifuged at 1500 × g for 4 min 4.The PRP fraction was separated and suspended with calcium chloride	•The half head treated with the combined therapy showed more hair regrowth (+16% vs. +12%) and larger hair fiber diameter (+35% vs. -4%)
El Taieb et al39
•Randomized controlled study •90 patients were randomized into three groups (30 patients per group)	•Topical 5% minoxidil twice daily (six puffs/ time) •3 PRP injections at 1-month intervals •Placebo cream	•10mL of blood was drawn and placed in two test tubes (5mL each) •Centrifuged at 3000 rpm for 10 min •The PRP fraction was separated and suspended in calcium gluconate •4mL PRP was used	•Patients treated with PRP had an earlier response for hair regrowth, reduction in short vellus hair percentage, and dystrophic hair, as compared with patients treated with minoxidil and control. •PRP resulted in significant improvements in cases of patchy AA, lesser for alopecia universalis, but not effective for alopecia totalis •PRP was more effective in AA treatment than topical minoxidil (5%) in clinical evaluation and dermoscopic findings

AA: alopecia areata; PRP: platelet-rich plasma; TrA: triamcinolone acetonide

PRP>TrA: PRP group showed significantly greater improvement than TrA group; PRP<TrA: PRP group showed significantly lesser improvement than TrA group; PRP=TrA: There was no significant difference between the PRP group and TrA group