Hairline and pattern
Your hairline changed. What else could it be?
You look at an old photo and the temples seem different. The tempting answer is to name the cause immediately. But one image cannot tell you whether the change is ongoing or why it happened.
A pattern is a clue, not a result
Hereditary hair loss often starts with a receding hairline or a bald spot at the top of the scalp in men, according to the American Academy of Dermatology (AAD). In this condition, hair follicles, the structures that grow hairs, gradually shrink. An early change at your temples is worth noticing, but a location alone does not confirm hereditary loss. [1]
Look at the pace as well as the place. A slow change around the temples or crown raises a different question from a sudden patch or a broad increase in shedding. The AAD notes that loss can begin gradually or abruptly and has many possible causes. You do not have to fit your scalp into one picture to take the change seriously. [1]
What may point elsewhere
More hairs on your brush after a major illness or a stressful period may be excessive shedding rather than the same process as gradual pattern loss. The AAD says this can start a few months after the event. The NHS also lists illness, stress, weight loss and iron deficiency among possible causes of temporary hair loss. These are possibilities, not a way to diagnose yourself. [2] [4]
A distinct patch or an irritated scalp deserves its own question. The AAD lists alopecia areata, an immune condition that can cause patches, and scalp infections among the many causes of hair loss. Hair can also be damaged by styles that pull on it. Those causes do not become hereditary pattern loss because they happen near your hairline. [1]
What to bring to an appointment
Try to describe when you first noticed the change, whether it appeared gradually or suddenly, and whether it is mostly at your temples, crown, in patches, or across your scalp. Mention any recent illness, new medicine, or scalp symptoms. A dermatologist uses your history and an examination of the scalp and hair; tests may be needed when a medical cause is suspected. [3]
If you are worried, see a GP. The NHS advises doing that before turning to a commercial hair clinic. You deserve an assessment that starts with the cause, not a product chosen from one photograph. [4]