While each specific diagnosis within this category is relatively uncommon, notable examples include dissecting cellulitis, eosinophilic pustular folliculitis, follicular degeneration syndrome (formerly referred to as “hot comb” alopecia), folliculitis decalvans, lichen planopilaris, and pseudopelade of Brocq. Scarring alopecia can also be part of more comprehensive conditions like chronic lupus erythematosus, where various organs of the body may be involved.

Despite the diversity of scarring alopecia forms, the common underlying theme is the potential for permanent and irreversible destruction of hair follicles, leading to their replacement with scar tissue.

Most cases of scarring alopecia initially manifest as small patches of hair loss that may gradually expand over time. While some instances of hair loss occur gradually and go unnoticed due to minimal symptoms, others are accompanied by intense itching, burning, and pain, progressing rapidly.

The appearance of scarring alopecia patches often differs from that of alopecia areata, with the edges of the bald patches appearing more irregular. The damage to the hair follicles occurs beneath the skin surface, often resulting in minimal visible changes on the scalp skin other than patchy hair loss. Affected areas may exhibit smoothness and cleanliness, or they could display signs of redness, scaling, pigmentation changes, or even raised blisters oozing fluids or pus.

While these visual cues can aid in diagnosis, identifying scarring alopecia based solely on hair loss patterns and scalp skin characteristics can be challenging. A definitive diagnosis often requires one or more skin biopsies to confirm the condition and specify the precise type of scarring alopecia. Typically, a small biopsy ranging from 2 to 4 mm in diameter is conducted and analyzed under a microscope. Dermatologists and pathologists examine the biopsy for indicators such as follicle destruction, deep scar tissue, and the presence and location of inflammation relative to hair follicles.