Common causes of thinning hair

Why can hair become thinner?

Hair changes can have more than one explanation, and the visible pattern does not establish a diagnosis on its own. A doctor considers when the change began, whether it affects the whole scalp or particular areas, and any changes in your general health. Some people notice shedding; others notice a different hairline or a widening part. These observations are useful to discuss but cannot replace an examination.

This guide summarises general background from the Australasian College of Dermatologists and Healthdirect. It does not tell you which condition you have or which care to choose. Keep clinical details for a consultation rather than sending them through our contact form. If you are unsure, your GP is another place to start, including when you have several concerns that may need to be considered together.

What is pattern hair loss?

Pattern hair loss describes a recognisable distribution of thinning that can occur in men and women. Some people notice a change around the hairline or crown; others notice thinning along the part. Family history may be relevant, but a similar appearance in relatives does not confirm the cause of your own hair change. A doctor may consider whether the pattern fits alongside other information.

Speak with a doctor if gradual thinning concerns you, if you are uncertain about the pattern or if you would like to understand the assessment process. Do not assume that every gradual change is pattern hair loss. A clinician can consider whether there are other contributing factors and whether further assessment is needed. Any discussion of care should be based on your individual circumstances.

Can stress, illness or postpartum changes cause shedding?

Telogen effluvium is a term used for a change in the hair cycle associated with increased shedding. It can follow events such as illness, significant stress, childbirth or rapid weight change. The shedding and the possible trigger may not occur at the same time, which is one reason a doctor asks about events before you first noticed the change. Not everyone with shedding has the same cause.

Postpartum shedding can be part of the history a doctor considers after childbirth, but it should not be assumed to explain every change during that period. Discuss persistent or concerning shedding with your GP, especially if there are other health changes. Increased shedding for three months or more is one example on our display-only checklist, not a rule that you must wait before speaking with a doctor.

A clinician may ask about eating patterns, recent illness and other relevant changes without assuming that any one factor explains the concern. Rapid weight change should be discussed in its wider health context. Avoid deciding on a cause from a single event or from information online. The doctor determines whether an examination or investigation is appropriate.

Could iron or thyroid issues be relevant?

Iron status and thyroid function are among the factors a doctor may consider when assessing some forms of thinning or shedding. These are not explanations to assign yourself from the appearance of your hair. A doctor considers your history, examination and any other symptoms before deciding whether blood tests are relevant. Testing is not an automatic requirement for everyone who has hair concerns.

If hair loss occurs with weight loss or fatigue, a GP is the right first step so your broader health can be considered. Ask what any proposed test is intended to clarify and how results would be discussed. A result needs clinical interpretation rather than being treated as a standalone explanation of hair loss. This site does not order tests or collect results.

What is alopecia areata?

Alopecia areata is a condition that can involve distinct areas of hair loss and is associated with the immune system. The appearance of a patch alone does not establish this diagnosis; other scalp conditions can also produce changes in particular areas. A doctor may examine the scalp and consider whether a dermatologist assessment is appropriate.

Arrange a conversation with your GP about unexplained patches rather than trying to identify the condition from a picture or a guide. Sudden or patchy loss with scalp pain or scarring belongs in our GP-first guidance. Tell the doctor about the timing and any scalp changes in the clinic’s own system. Our enquiry pathway cannot assess a patch or determine its cause.

Can tension on the hair cause traction-related loss?

Traction-related hair loss can be associated with repeated tension on the hair, including from tightly pulled styles. A doctor may ask about styling habits and examine where changes have occurred. That history is one part of an assessment, not proof that styling explains every hair change. Discuss discomfort, scalp changes or a persistent change with a doctor.

If there is scalp pain or scarring alongside sudden or patchy loss, see your GP first. You can ask whether your usual hair-care practices are relevant, but do not treat general information as an individual plan. A doctor can decide whether further assessment is needed. This guide does not recommend products or make promises about what will happen after a change in routine.

When should I choose a GP rather than an enquiry?

A GP is the right first step for sudden or patchy loss with scalp pain or scarring, hair loss with weight loss or fatigue, or anyone under 18. Your GP can also assess other hair concerns; this is not a pathway reserved only for those examples. Our suitability checklist is non-scored and does not collect or store responses.

If you choose to make an adult contact enquiry, the partner clinic can explain assessment arrangements and costs. It is not a diagnosis or a booking. Read what an assessment may involve and ask questions before deciding. The sources below provide further general background; their inclusion is not an endorsement of this site or its partner.