Subpericranial and epidural abscess with skull osteomyelitis as a complication of microneedling for alopecia: A singular case report

Abstract

Background:

Subpericranial hematoma (SPH) is unusual in adults and is usually seen in neonates as cephalohematoma. Closed scalp hematoma is usually not associated with infection and abscess formation.

Case Description:

A 28-year-old male presented with complaints of swelling on the left forehead. The patient at that time was on self-treatment for alopecia following a routine of application of minoxidil hair spray followed by microneedling with his derma roller. Radiological evaluation revealed a mass in the left frontal scalp region and communicating through frontal bone defect with mass in the extradural space. The patient was planned for surgical evacuation of the abscess under general anesthesia.

Conclusion:

Subpericranial abscess is an unreported complication of SPH in an adult. SPH can get infected with procedures like microneedling without an open wound.

INTRODUCTION

Subgaleal hematoma (SGH) is commonly associated with traumatic head injury. It may or may not be associated with intracranial injury. Subpericranial hematoma (SPH) is unusual in adults and is usually seen in neonates as cephalohematoma.[7] Closed scalp hematoma is usually not associated with infection and abscess formation. Abscess formation under the galea layer is usually due to invasive procedures such as electroencephalography, neurosurgical procedures, or due to penetrating scalp or head injury.[3] Extension of infection from nearby structures can be seen; scalp skin which in proximity to the galea, superficial skin infections can invade the galea and may present as a scalp abscess.[5]

We present a case of infected SPH with a microneedling procedure for alopecia treatment resulting in the formation of subpericranial abscess with intracranial epidural abscess. This case report has been reported in line with the CARE criteria and revised SCARE criteria of 2023.[9]

CASE PRESENTATION

A 28-year-old male presented with complaints of swelling on the left forehead anterior to the hairline for 2 months. It was not painful, no complaints of increase in size. The patient had no complaints of headache, loss of consciousness, or vomiting. The patient had a history of hit on head by the edge of door 3 months back while brisk walking, followed by mild swelling and pain at the site of impact, but there was no wound/abrasion/laceration, so the patient ignored the swelling on the forehead. The patient at that time was on self-treatment for alopecia following a routine of application of minoxidil hair spray followed by microneedling with his derma roller without aseptic precautions [Figure 1A]. On examination, swelling was noted in the left frontal region, with overlying normal skin; no dilated or erythematous skin was noted. The swelling was firm, mildly compressible, and mild tenderness was noted on pressing; the slip sign was negative [Figure 1B and C]. On deep palpation, bony margins were appreciable. Radiological evaluation revealed a mass measuring 1 × 0.8 cm in the left frontal scalp region and communicating through frontal bone defect with a mass of size 2.8 × 1.5 cm in the extradural space, giving a dumbbell appearance. The mass was T1 hypointense, T2 and fluid-attenuated inversion recovery hyperintense, showing diffusion restriction and peripheral rim enhancement on contrast administration, giving the impression of abscess [Figure 2A-F]. The patient was planned for surgical evacuation of the abscess under general anesthesia in supine position with head in neutral position. The patient was not given any preoperative medication apart from perioperative prophylaxis of injection ceftriaxone 1 g stat dose before incision. A hairline curvilinear incision was taken for cosmetic reasons to avoid a forehead scar; scalp flap was lifted in layers to reveal the subpericranial location of the abscess [Figure 3A]. Needle aspiration of the abscess through the periosteum showed pus in the hub of the syringe but did not yield any significant amount; therefore, a cruciate incision on the pericranium over the abscess was given for egress of the pus, which was greenish yellow, foul-smelling, and very thick [Figure 3B]. The pericranium was removed circumferentially to delineate the bony defect. The defect was enlarged to perform a 2 × 2 cm mini craniotomy as the pus was very thick. Pus and flakes removal was done; lavage was given thoroughly using hydrogen peroxide, and vancomycin instilled saline till visible flakes vanished and bleeding was noted. Titanium mesh was fixed after instillation of cavity with vancomycin powder to avoid forehead depression after surgery. Closure was done in layers [Figure 3C-F]. The patient was extubated, and the rest of hospital stay was uneventful. Intraoperative cultures were sent for analysis but turned out to be sterile. The patient was subsequently discharged to home on postoperative day 2. Postoperatively, the patient was kept on injection ceftriaxone 1 g bis in die (BD) and injection amikacin 500 mg OD for 3 days, followed by tablet faropenem 300 mg BD with tablet linezolid 600 mg BD for 14 days. The piece of bone as shown in Figure 3C, along with overlying pericranium and organized pus, was sent for histopathological examination, which showed dense chronic inflammatory exudate with negative acid–fast bacilli staining. Contrast-enhanced computed tomography scan done at 3-month follow-up revealed complete resolution of previous findings with blood mixed vancomycin powder showing hyperdensity in the bony cavity and mesh plate overlying the mini craniotomy [Figure 4A and B]. The patient had no neurological deficit at any given point in time. Patient on follow up had good cosmetic outcome [Figure 4C and D].

Figure 1:

(A) Dermaroller device used for scalp microneedling by the patient. (B) and (C) Preoperative clinical photograph showing swelling over the left frontal scalp anterior to hairline (black arrow).

Figure 2:

(A) Non-contrast Computed tomography (NCCT) axial view of the brain showing a subtle hypodense area of size 2.8 cm x 1.5 cm in the left frontal region (blue arrow). (B) NCCT bone window demonstrating focal calvarial defect in the left frontal bone (red arrow). (C) Axial and (D) Coronal T2-weighted (T2W) Magnetic resonance imaging (MRI) revealing a lobulated hyperintense collection of size 2.8cm x 1.5cm in intracranial extradural space in left frontal region (blue arrow); in communication with another 1.0 cm x 0.8 cm collection in the extra-cranial/subpericranial space. (red arrowhead). (E) Axial and (F) Coronal T1-weighted (T1W) contrast enhanced MRI showing peripheral rim enhancement on contrast administration (red arrowhead).

Figure 3:

(A) Intraoperative exposure revealing inflamed pericranial tissue and collection beneath pericranium (white arrow). (B) Drainage of thick purulent material after cruciate incision (black arrow). (C) Intraoperative photograph demonstrating mini-craniotomy, done using the frontal bone fracture seen in the centre of bone piece. (D) Intraoperative view after the removal of overlying bone post-craniotmy (black arrow). (E) Post-debridement and lavage using hydrogen peroxide and vancomycin instilled saline showing raw dural surface giving appearance of the cleaned bony defect (black arrow). (F) Reconstruction of the defect using a titanium mesh with vancomycin powder instilled in the cavity (black arrow).

Figure 4:

(A) and (B) Follow-up axial NCCT head demonstrating postoperative changes with hyperdense collection of 2cm x 1cm with a craniotomy defect of 2cm(red arrow) and (B) titanium mesh in-situ (red arrow). (C) Early postoperative photograph at 2 weeks. (D) Follow-up clinical image at 3 months demonstrating good wound healing and hair regrowth

DISCUSSION

The subpericranial space is a potential location between the overlying pericranium and skull bone below.[8] Pericranium is the deepest layer of scalp, which is adhered to the skull and harvested during neurosurgical procedures for duroplasty or defect coverage. Hematoma collection in subpericranial location is commonly seen in newborns during the process of birth where they are termed cephalohematomas. A cephalohematoma is usually located in occipital or parietal regions in newborns. SPH in an adult and its eventual culmination into subpericranial abscess with intracranial extradural extension has previously been unheard of.

Any scalp hematoma without open wound usually is bound to resolve on its own unless any contiguous or spread from other areas is seen.[10] Invasive procedures over inflamed skin cause inoculation of pathogens deep into the layers of scalp which can be linked to in this case where the patient was on self-treatment using a roller microneedling instrument for alopecia. Microneedling is to be avoided on inflamed skin as it creates micropores which can cause seepage of skin pathogens.[4,6] The patient in our report had a frontal bone fracture which could have resulted in the formation of SPH; continued roller microneedling procedure on inflamed skin which could have resulted in infection of SPH leading to formation of abscess; and presence of fracture could have led to intracranial extradural extension of the abscess. In reported cases of SGH, all except one were reported in neonates, infants, and children.[1,2] The exception mentioned was a 39-year-old female who had SGH contralateral to the scalp injury which was managed conservatively using compression bandage application.[1]

In our case, we planned for surgery as the location was anterior to the hairline; forehead aspiration could have resulted in mark, with the possibility of nonaspiration or fistula, ultimately leading to surgical intervention and cosmetic deformity. Subpericranial location and extension to intracranial extradural extension of the abscess made the decision for surgery easier. As the cavity was clean at the end of the procedure, we decided to place titanium mesh to prevent cosmetic forehead deformity and covered the edges of the mesh with pericranium to avoid tethering to the overlying scalp. The porous structure of mesh would also allow any potential blood collection in the cavity to come out, preventing formation of an extradural hematoma. Vancomycin powder instillation was done as a measure of local antisepsis.

While there have been multiple reports of infected SGH following traumatic head injury, as mentioned, but to the authors’ knowledge and after extensive literature review, there was no report of SPH or subpericranial abscess in an adult. This report provides the only evidence of existence of this entity in an adult patient and outside of the neonatal age group and its successful management of this condition.

CONCLUSION

Subpericranial abscess is an unreported complication of SPH in an adult. SPH can get infected with procedures like microneedling without an open wound. Deep scalp location makes this a surgical entity rather than an aspiration procedure. While the unsupervised use of microneedling procedures is on the rise, their judicious and monitored use is advocated to prevent these unforeseen complications.

Ethical approval:

The Institutional Review Board has waived the ethical approval for this study.

Declaration of patient consent:

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given consent for their images and other clinical information to be reported in the journal. The patient understands that the patient’s names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

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