Every summer the same panic - a brush full of hair, a clogged drain, and the conclusion that your hair is falling out. Dermatologist Cristina de Hoyos says a different question has to be answered first: is the hair actually falling out, or is it breaking?

"Shedding and breakage can coexist, especially in summer, but they are different processes," she explains. In shedding, the hair separates from the root. In breakage, the follicle stays in place and the hair itself gives way somewhere along its length. The distinction is not academic - one is temporary and seasonal, the other means weakened hair that needs an entirely different kind of care.

How to tell the difference

Katrina Riera advises looking closely at a hair from the brush. If one end has a small whitish bulb, the hair has separated from the follicle and this is genuine shedding. No bulb, and it is most likely breakage. De Hoyos adds: "if both ends are thin or look frayed, it most likely broke".

The second indicator is length. With normal shedding, the hairs are as long as the rest of the hair. With breakage they are short and uneven, and usually come as a package with split ends, rough texture, lost shine and hair that is hard to detangle. "Breakage usually shows up as hair losing quality, not quantity," the dermatologist sums up.

The number that settles the summer panic

Here comes the figure worth remembering: "Physiologically we lose between 50 and 100 hairs a day, regardless of whether the hair is long or short". Length changes nothing about the number - it only changes how much space those hairs occupy. Fifty centimetres looks far more dramatic than five. Riera confirms the same: the same number of long hairs creates the impression of far greater loss.

There is a second optical effect. When hair is long and washed less often, hairs that have already shed stay trapped for days, then come out all at once in the shower. It looks like sudden loss. It is not.

What actually damages hair in summer

Riera explains that sea salt and chlorine from pools dehydrate the hair fibre, increasing dryness and the tendency to break. Add straighteners, a hairdryer on high heat and tight hairstyles - and the damage accumulates. De Hoyos warns that towards the end of summer two things can overlap: more breakage from a damaged shaft, and a temporary increase in seasonal shedding.

The mistakes are predictable. First, washing too rarely - summer brings sweat, salt, chlorine, sand and sunscreen residue, and prolonged contact irritates the scalp. Second, damp roots for hours: despite the heat, humidity in the air prolongs drying. Third, too much heat from appliances on a fibre already dried out by sun and seawater.

Practically: a hat or cap for less exposure, sunscreen for hair and hydrating masks, rinsing with fresh water immediately after swimming, detangling from the ends upward, and looser hairstyles.

When it is no longer seasonal

Seasonal shedding lasts six to twelve weeks and can start before autumn. If it lasts more than three months, if density has visibly decreased, or if the scalp is showing, it is time for an examination. De Hoyos adds more signs: a widening parting, clear bare patches, itching, pain, inflammation or flaking. An examination is also worth it if the shedding coincides with anaemia, hormonal changes, a recent illness, significant weight loss or major stress.

The most important sentence in the whole piece is the dermatologist's last one: breakage and shedding from the follicle require different treatments. A mask improves a dry fibre, but does nothing when the problem lies in the hair cycle. So: diagnosis first, bottle second - and the industry usually offers the reverse order.