Hair
Background
Hair and hair follicle analysis can provide the clinician with important, often diagnostic information about conditions that can affect the hair follicle unit including congenital diseases, metabolic disorders, infections and other causes of alopecia.
A wide range of laboratory tests are available to the clinician including hair shaft/bulb examination and scalp biopsies. Other ancillary tests such as immunofluorescence electron microscopy may also be required for the diagnosis of some conditions.1,2
In general, two punch biopsies of scalp are usually submitted; one from the affected area and one from “normal” scalp.
Punch biopsies are taken parallel to the hair follicles, thus minimising tangential sectioning and should include epidermis, dermis and a generous amount of subcutaneous fat.
Record the patient identifying information and any clinical information supplied together with the specimen description as designated on the container. See overview page for more detail on identification principles.
See general information for more detail on specimen handling procedures.
Inspect the specimen and dictate a macroscopic description.
External Inspection
Orientate and identify the anatomical features of the specimen.
Photograph the intact specimen if required.
Procedure
Describe as stated by the clinician.
Specimen description
Describe the following features of the specimen:
For each describe:
- Diameter (mm)
- Depth (mm)
- Appearance
Dissection
Once received the biopsy should be fixed in formalin for 24 hours prior to dissection.
Sections can be taken horizontally or vertically depending on the laboratory protocol although transverse sections have been accepted as the recommended standard in a consensus statement from a working group of alopecia experts (Olsen et al).3
For transverse sections, the punch biopsy is divided horizontally into two pieces about 2mm deep to the epidermal surface. Both cut surfaces are then embedded face down.
Generally horizontal biopsies are best if only one biopsy is submitted and essential for investigation of non-scarring alopecia. Vertical or horizontal sections may be used in scarring alopecia and both have advantages and disadvantages in this setting. If two biopsies are received some centres perform one vertical and one horizontal.
Once processed, serial sections are taken towards the skin surface and deep aspect of the specimen.
Strands of hair do not require dissection or processing but can be mounted directly on to glass slides with mounting medium and a coverslip for microscopic examination.
Internal Inspection
Not required.
Processing
Submit all sections as described above.
Routine special staining with periodic acid Schiff’s diastase (PAS-D) is useful when investigating alopecia.
Record details of each cassette.
An illustrated block key similar to the one provided may be useful.
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Casette id
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Site
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No. of pieces
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A-B
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Skin/hair
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Acknowledgements
Dr Craig James for his contribution in reviewing and editing this protocol.
References
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Allen DC, Cameron RI, editors. Histopathology Specimens: Clinical, pathological and laboratory aspects. 2nd ed. London: Springer-Verlag; 2012.
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Olsen EA, Bergfeld WF, Cotsarelis G, Price VH, Shapiro J, Sinclair R, et al. Summary of North American Hair Research Society (NAHRS) – sponsored Workshop on Cicatricial Alopecia, Duke University Medical Center, February 10 and 11, 2001.
J Am Acad Dermatol. 2003;48:103–10.