Hair falling out in chunks points to a specific disruption in your hair’s growth cycle, not ordinary shedding. Normal daily loss ranges from about 30 to 100 hairs, and those tend to come out individually throughout the day. When you’re pulling out clumps in the shower or finding patches on your pillow, something has pushed a large number of follicles out of their growth phase at once, or your immune system is attacking the follicles directly. The cause matters because some types of chunk hair loss resolve on their own within months, while others need treatment to prevent permanent damage.
Telogen Effluvium: The Most Common Cause
Under normal conditions, only about 5% of your hair is in its resting (shedding) phase at any given time. In telogen effluvium, a physical or emotional stressor forces up to 70% of your actively growing hairs into that resting phase all at once. Two to three months later, all those hairs fall out together, which is why you suddenly notice clumps rather than a gradual thin-out.
The list of triggers is long: high fever, severe infection, major surgery, psychological stress, childbirth, thyroid problems, crash diets low in protein, and certain medications including some blood pressure drugs, antidepressants, and anti-inflammatory painkillers. Stopping birth control pills is another well-known trigger. The hair loss itself doesn’t start during the stressful event. It shows up weeks or months later, which makes it hard to connect cause and effect without thinking back.
The good news is that telogen effluvium is almost always temporary. Once the underlying trigger resolves, hair typically begins regrowing within six months. The bad news is that the shedding can be dramatic and frightening while it lasts, and if the stressor continues (ongoing nutritional deficiency, chronic stress, untreated thyroid disease), the shedding can become chronic.
Alopecia Areata: Coin-Sized Bald Patches
If your hair is coming out in round or oval patches rather than thinning all over, the likely culprit is alopecia areata. This is an autoimmune condition where your immune system mistakenly attacks your own hair follicles, causing inflammation that shuts down growth. The patches are typically coin-sized, smooth, and can appear on the scalp, beard, eyebrows, or eyelashes. The onset is sudden, and you may notice a clump of hair on your pillow with a corresponding bare spot the next morning.
Researchers believe both genetic susceptibility and environmental triggers play a role, though the exact cause isn’t fully understood. Treatment options have expanded significantly in recent years. The FDA approved the first oral medication targeting the specific immune pathway involved (a JAK inhibitor called baricitinib) in 2022, followed by ritlecitinib in 2023 for patients 12 and older. A third option, deuruxolitinib, received approval in 2024. These medications work by dialing down the immune attack on follicles. For milder cases, steroid injections into the patches or topical treatments are often tried first.
Postpartum Shedding
If you recently had a baby, what you’re experiencing is extremely common and has a predictable timeline. During pregnancy, elevated hormones keep hair in its growth phase longer than usual, which is why many pregnant women notice thicker hair. After delivery, those hormones drop and all that “extra” hair enters the shedding phase at once.
Postpartum hair loss typically begins around 2 to 4 months after delivery, peaks at about 5 months, and resolves by around 8 months, though it can take up to a year. The clumps can be alarming, but the follicles are healthy and will cycle back into growth on their own.
Iron Deficiency and Nutritional Gaps
Low iron is one of the most underdiagnosed causes of hair loss, particularly in women who menstruate. Standard blood tests may show your iron levels as “normal” when they’re actually too low for healthy hair growth. The threshold that matters isn’t the same one used to diagnose anemia. Research suggests that hair shedding can occur when ferritin (your body’s iron storage marker) drops below 60 ng/mL, even though many labs flag levels as low only when they fall below 10 or 15. One study found that using a cutoff of 41 ng/mL caught 98% of iron-deficient cases, compared to only 59% when using the traditional cutoff of 10 to 15.
If you’ve been losing hair and your doctor says your iron is “fine,” it’s worth asking for the specific ferritin number. Levels between 40 and 60 ng/mL appear to be the minimum needed for adequate hair growth in premenopausal women. Other nutritional deficiencies that contribute to shedding include low protein intake, vitamin D deficiency, and zinc deficiency, all of which are more common in people who follow restrictive diets.
Fungal Scalp Infections
Ringworm of the scalp (tinea capitis) causes hair to break off at the surface, leaving round bald patches dotted with black stubble where the shafts snapped. In people with lighter hair, the dots appear blonde instead. The affected areas are often itchy, with dry, raised scales or crusty bumps that may drain pus and feel tender. This is more common in children but can affect adults, and it spreads through direct contact or shared combs, hats, and pillows. Unlike alopecia areata, which leaves smooth bare skin, fungal patches look rough and inflamed. Oral antifungal treatment is needed because topical creams can’t reach the infection inside the hair follicle.
Chemotherapy and Medication-Related Loss
Chemotherapy targets rapidly dividing cells, and hair follicle cells are some of the fastest-dividing in the body. Hair shedding from chemotherapy typically begins within 14 days of the first treatment and often becomes pronounced by 2 to 3 weeks. Unlike telogen effluvium, where hairs enter a resting phase and fall out at the root, chemotherapy can fracture the hair shaft itself, causing breakage and shedding simultaneously. Hair usually begins regrowing after treatment ends, though the texture and color may temporarily change.
Other medications that can trigger noticeable shedding include retinoids (used for acne and skin conditions), beta-blockers, calcium channel blockers, and some antidepressants. This type of loss tends to be diffuse rather than patchy.
Scarring vs. Non-Scarring Hair Loss
This distinction is the single most important thing to pay attention to. In non-scarring hair loss (which includes telogen effluvium, alopecia areata, and postpartum shedding), the hair follicle itself stays intact. Even if you lose dramatic amounts of hair, regrowth is possible because the follicle is still alive beneath the surface.
Scarring alopecia is different. The follicle is permanently destroyed and replaced with scar tissue. The bald patches look smooth and shiny, and if you look closely, you won’t see any tiny pore openings where hair used to emerge. Some forms also cause redness, flaking, or blistering. This type of hair loss is irreversible once the scarring is complete, which is why early recognition matters. If your bald patches look glassy and you notice any burning, tenderness, or skin changes around them, that warrants prompt evaluation.
What Doctors Look For
A dermatologist evaluating chunk hair loss will typically start with a hair pull test, gently tugging on a small section of about 60 hairs to see how many come free. If more than 20% of the pulled hairs come out, that suggests active shedding consistent with telogen effluvium. They’ll examine the bulb end of those hairs under a microscope to determine whether the hairs are falling out at the root (indicating a growth-cycle problem) or breaking mid-shaft (indicating damage or infection).
Blood work usually includes thyroid function, a complete blood count, and ferritin levels. If patchy loss is present, a scalp biopsy may be done to distinguish between alopecia areata, scarring alopecia, and fungal infection. Bringing in a collection of your shed hair, or photos showing how the loss has progressed over time, gives your doctor useful information that a single office visit can miss.