Clinical Notes
Hair Loss in Adults: A Practical Diagnostic Approach
Not all hair loss is the same. Here’s how we distinguish common patterns and decide when tests are needed.
2/21/20261 min read
First: define the pattern
The most useful first step is identifying the pattern:
- Diffuse shedding (often telogen effluvium)
- Pattern thinning (androgenetic alopecia)
- Patchy loss (alopecia areata, tinea, traction)
- Scarring signs (needs early attention)
The 3 questions that change the diagnosis
- When did it start? Sudden vs gradual
- Is shedding or thinning? Hair on pillow/shower vs reduced density
- Any scalp symptoms? Itch, scale, burning, pain
When tests may be needed
Tests are not for everyone. We consider them when history and exam suggest a systemic driver:
- iron deficiency
- thyroid imbalance
- vitamin D deficiency (in selected cases)
- hormonal factors (when clinically indicated)
When to worry
Seek evaluation early if you have:
- widening patches
- scalp pain/burning
- shiny/scarred areas
- associated eyebrow/eyelash loss
Key message
Hair loss is a diagnosis, not a single disease. A structured assessment saves time and prevents unnecessary treatments.