Alopecia areata incognita: a hypothesis

Area of Science:

• Dermatology
• Trichology
• Hair Biology

Background:

• Alopecia areata is characterized by patchy hair loss.
• The underlying mechanism for localized hair fall remains unclear.
• Existing hypotheses do not fully explain the stochastic nature of affected areas.

Purpose of the Study:

• To propose a novel hypothesis explaining the localized hair loss in alopecia areata.
• To elucidate the specific hair cycle phase associated with the onset of alopecia areata patches.
• To differentiate the presentation of alopecia areata from other forms of hair loss.

Main Methods:

• Hypothetical model based on hair cycle dynamics.
• Analysis of hair cycle phases in affected individuals.
• Review of epidemiological data and clinical presentations.

Main Results:

• A hypothesis is proposed where alopecia areata occurs in areas with hairs simultaneously in the early anagen VI subphase.
• Individuals with low percentages of telogen hairs are more susceptible to developing distinct alopecia areata patches.
• Androgenetic alopecia patients with co-existing alopecia areata tend to present with diffuse hair loss (alopecia areata incognita).

Conclusions:

• The timing of hair follicles entering the anagen VI subphase is critical for alopecia areata patch formation.
• Telogen percentage is a key factor differentiating alopecia areata from other alopecias.
• Alopecia areata incognita represents a distinct presentation in patients with underlying androgenetic alopecia.