Telogen Effluvium: Understanding Temporary Hair Loss in the UK

Telogen effluvium is one of the most common causes of temporary hair loss in the UK. Unlike genetic conditions such as male pattern baldness, which happen gradually over many years, telogen effluvium often appears as a sudden, noticeable increase in hair shedding across the entire scalp.

To understand this condition, it is helpful to look at the hair growth cycle. At any given time, roughly 85% to 90% of your hair is in the 'anagen' (growth) phase, while the remainder is in the 'telogen' (resting) phase. Telogen effluvium occurs when a significant stressor shocks the body, causing a larger proportion of hairs—sometimes up to 30%—to stop growing and enter the resting phase simultaneously. Approximately three months after this trigger, these hairs begin to fall out.

In many cases, telogen effluvium is a physical reaction to a specific event that occurred several months before the shedding started. Common triggers identified by UK health professionals include:

• Severe Stress or Trauma: Significant emotional distress or bereavement can shock the system.
• Physical Illness: High fevers, severe infections (including recovery from COVID-19), or major surgery frequently lead to temporary thinning.
• Nutritional Deficiencies: Low levels of iron (ferritin), vitamin B12, or zinc can disrupt the hair growth cycle.
• Rapid Weight Loss: Crash dieting or a sudden decrease in protein intake can deprive hair follicles of the nutrients they need.
• Medication Side Effects: Certain drugs, such as beta-blockers, anticoagulants, or some antidepressants, may trigger shedding in some individuals.

The primary symptom of telogen effluvium is a diffuse thinning of the hair. You may notice more hair than usual in your hairbrush, on your pillow, or in the shower drain. Because the hair loss is widespread, you are unlikely to see the distinct 'M-shaped' receding hairline or the bald patch at the crown associated with androgenetic alopecia.

Key signs include:

• Increased shedding when washing or brushing.
• A feeling that your hair is less 'dense' or that your ponytail feels thinner.
• The presence of 'club hairs'—hairs that have fallen out and have a small, white bulb at the root.
• The scalp usually appears healthy with no signs of redness, scarring, or scaling.

It is important to distinguish telogen effluvium from male pattern baldness (androgenetic alopecia). While both involve hair loss, their mechanisms and outcomes are different. Male pattern baldness is permanent and caused by the sensitivity of hair follicles to dihydrotestosterone (DHT), leading to a slow miniaturisation of the hair.

In contrast, telogen effluvium is a temporary 'pause' in the growth cycle. The follicles themselves remain healthy and capable of producing new hair. Once the trigger—be it stress, illness, or diet—is removed or resolved, the hair cycle typically returns to normal. However, for men already predisposed to genetic balding, a severe episode of telogen effluvium can sometimes unmask or accelerate the appearance of existing thinning.

The good news is that telogen effluvium is usually self-correcting. Most people find that the shedding stops within six months, and the hair begins to regrow soon after. In the UK, management typically focuses on identifying and treating the underlying cause:

• Nutritional Support: If a blood test reveals a deficiency, a doctor may recommend iron or vitamin supplements.
• Stress Management: Practising mindfulness or seeking support for anxiety can help the body recover from a physiological shock.
• Gentle Hair Care: Avoiding harsh chemical treatments or excessive heat during the shedding phase can prevent further mechanical damage to remaining hair.

There is no specific 'cure' for the shedding itself, as the hairs that are falling out now were already pushed into the resting phase months ago. Patience is key during the recovery period.

If you are concerned about sudden hair loss, consulting an online GP is a sensible first step. While telogen effluvium is temporary, it is essential to rule out other medical conditions that could cause similar symptoms.

You should book a consultation if:

• The hair loss is accompanied by other symptoms such as fatigue, cold intolerance, or changes in your skin.
• The shedding has lasted for more than six months (chronic telogen effluvium).
• You have developed patchy bald spots or an itchy, painful scalp.
• You believe your hair loss is related to a medication you have recently started.

An online GP can review your medical history, suggest necessary blood tests, and provide guidance on nutrition or stress management to help support your recovery.