Title : Herpes zoster ophthalmicus following platelet-rich plasma therapy for androgenetic alopecia: A probable adverse reaction
Abstract:
Case: A man in his 60s presented with a 7-day history of progressive left periorbital oedema and pruritic vesicular following ipsilateral platelet-rich plasma (PRP) injections for androgenetic alopecia (AA). Pain and swelling started on the day of injection. His past medical history included ischaemic cardiomyopathy, cerebrovascular infarction, atrial fibrillation, hypertension, asthma, benign prostatic hyperplasia, and gastro-oesophageal reflux disease. Initial assessments attributed the reaction to an allergy and later to bacterial cellulitis, for which he received oral corticosteroids and antibiotics. Despite this, symptoms worsened, prompting Emergency Department attendance where left periorbital oedema, vesicles, chemosis, and conjunctival hyperaemia were noted. Vision and ocular motility were preserved, and there were no other signs of ocular involvement.
CT imaging demonstrated preseptal cellulitis without orbital involvement. Lesional swabs were positive for varicella zoster virus (VZV) on polymerase chain reaction (PCR), and VZV IgG was detected serologically, confirming herpes zoster ophthalmicus (HZO) with secondary preseptal cellulitis. Bacterial swabs and MRSA screening were negative. He was treated with intravenous aciclovir and ceftriaxone, with rapid clinical improvement. At follow-up, he had residual post-herpetic neuralgia and dermatomal pigmentation, managed with oral gabapentin.
Discussion: PRP is widely used for AA and is typically safe, with minimal reported side effects (Chen et al., 2018). However this represents the second reported case of HZO temporally associated with PRP administration, as Zeineddine et al. also described a case of HZO activation within 24 hours of PRP therapy (Zeineddine et al., 2023). The temporal and anatomical association suggests a possible causal relationship, supported by a Naranjo Adverse Drug Reaction Causality Scale score of 5 (“probable”) (Naranjo et al., 1981).
The platelet- rich concentrate in PRP extracted from centrifuged autologous blood has a high concentration of multiple growth factors and cytokines, which promote hair growth in AA (Alves et al., 2018). HZO occurs when VZV has been dormant in the trigeminal ganglion and reactivates in the ophthalmic branch of cranial nerve V (Shaikh et al., 2002). One hypothesis is that the growth factors and cytokines in PRP disrupt the local immune system equilibrium, providing latent VZV an opportunity to reactivate (Gershon et al., 2010). Alternatively, inadvertent infection could result from non-autologous sample injection, although VZV migrates to nerve root ganglions via T-lymphocytes and T-lymphocytes should be removed from PRP during centrifugation (Alves et al., 2018). Considering the negligible admission CRP, negative bacterial swabs and bacterial superinfection being a common severe complication of HZO, superimposed secondary cellulitis is more likely than primary cellulitis (Davies et al., 1996).
Conclusion: This case highlights the second reported instance of HZO following PRP therapy. While the exact mechanism remains unknown, the close temporal and anatomical association strongly suggests a causal relationship. Cross-contamination of PRP samples may explain this adverse event, whilst immunomodulatory effects may enable local latent VZV reactivation. Given the potential emerging side effects associated with PRP, strict standardised protocols must be developed. PRP should only be performed by trained medical professionals.
