Alopecia: Histologic Changes
January 1989
in “
PubMed
”
androgenic alopecia alopecia areata trichotillomania inflammatory scarring alopecias pseudopelade anagen effluvium telogen effluvium follicular plugging hair follicles fibrous tracts actinic damage dermal inflammation anagen/telogen ratio miniaturization of the hair follicle involution scarring elastic fiber stains male pattern baldness female pattern baldness hair pulling disorder scarring alopecia pseudopelade anagen effluvium telogen effluvium hair follicles fibrous tracts sun damage skin inflammation hair growth cycle hair follicle shrinkage hair follicle regression scarring elastic fiber stains
TLDR The review found that specific changes in scalp tissue can help diagnose different types of hair loss.
The 1989 review "Alopecia: histologic changes" identified the major types of alopecia that can be diagnosed histologically as androgenic alopecia, alopecia areata, trichotillomania, inflammatory scarring alopecias, pseudopelade, and anagen and telogen effluviums. Common histologic features in chronic alopecias were found to include follicular plugging, decreased numbers of hair follicles, increased fibrous tracts, and superficial changes of actinic damage. Specific changes that aid in diagnosis include the presence of actinically damaged skin, the presence and site of dermal inflammation, a decrease in the numbers of hair follicles and a reversal of the anagen/telogen ratio, miniaturization of the hair follicle, evidence of involution, and the presence of scarring as demonstrated with elastic fiber stains. These histologic changes allowed for a reasonably specific diagnosis of alopecia.
