When the change began matters
Increased shedding can appear weeks or months after an illness, surgery, childbirth, major stress, or a restrictive diet. This delayed shedding is called telogen effluvium.[1]
Because the delay can be substantial, the relevant history extends beyond the week hair first seemed different. Recent health changes and medicines may matter even if they initially seemed unrelated.
Gradual thinning may follow another pattern, including inherited hair loss. A widening part, patchy areas, or changes at the hairline are useful details to describe, without assuming they identify a diagnosis on their own.
The scalp gives additional clues
An examination can look at the distribution of loss, the condition of the scalp, and whether hairs break or come away easily. A dermatologist may use a gentle hair-pull test and ask about hair care and family history.[2]
Pain, itching, redness, scaling, or rapid and unusual loss deserves assessment.[1] Those details can point the investigation in a different direction from otherwise uncomplicated shedding.
Blood tests are selected for a reason
Testing may help when the history or examination suggests a nutritional deficiency, thyroid problem, or another medical condition. Some cases need a scalp biopsy or another assessment; many can be understood from the history and examination.[1][2]
There is no single blood panel that explains every pattern of hair loss. Dates and comparable photographs can be useful starting records. Include the first noticeable change, relevant illnesses or weight changes, new medicines, and any scalp symptoms.
