Hair Science
Background science on hair anatomy, cycling, and biologic regulation.
Summary
What it is
Foundational concepts used to understand hair growth and disease.
Who it affects
Readers seeking a scientific orientation to hair biology and terminology.
Key clinical facts
- Mechanistic explanations are simplified for educated lay readers.
- Claims are tied to peer-reviewed sources.
Evidence level
Detailed sections
Background
Human hair follicles are dynamic mini-organs with cyclic growth phases and interactions with skin, immune, and endocrine systems. [1] [2]
Causes / Mechanisms
Hair cycling is regulated by signaling pathways and local stem cell dynamics; hormonal and inflammatory signals may alter cycle duration and follicle size in some diseases. [3] [4]
Symptoms / Presentation
Scientific concepts are used to interpret clinical patterns such as diffuse shedding, patterned miniaturization, or inflammatory scalp findings. [1]
Diagnosis
Diagnostic tests often map clinical findings to biologic processes (e.g., identifying miniaturization or inflammation) rather than measuring hair cycle signaling directly. [1]
Treatment Options
Scientific mechanisms can inform hypotheses about interventions, but clinical effectiveness requires condition-specific evidence. [1]
Prognosis
Understanding baseline biology can clarify why some conditions relapse, remit, or progress over time. [1]
Citations
References
- The biology of hair follicles. N Engl J Med. 1999. PMID: 10441606.
- Schneider MR, Schmidt-Ullrich R, Paus R. The hair follicle as a dynamic miniorgan. Curr Biol. 2009. PMID: 19211055.
- Stenn KS, Paus R. Controls of hair follicle cycling. Physiol Rev. 2001. PMID: 11152763.
- Lin X, Zhu L, He J. Morphogenesis, Growth Cycle and Molecular Regulation of Hair Follicles. Front Cell Dev Biol. 2022. PMID: 35646909.