Bald spots are not a normal part of everyday hair shedding. Losing 50 to 100 hairs a day is completely typical, and you usually won’t notice it because new hair grows in at the same pace. But when hair disappears in distinct patches, leaving visible bare skin on your scalp, beard, or eyebrows, something specific is causing it. The good news is that most causes of patchy hair loss are treatable, and many resolve on their own.
Normal Shedding vs. Bald Spots
The hair you find on your pillow, in the shower drain, or on your brush is almost always normal shedding. Each hair follicle cycles through growth, rest, and release phases independently, so the loss is spread evenly across your scalp. You never see a bare patch from routine shedding alone.
Bald spots are different. They appear as distinct areas where hair is missing or visibly thinner, sometimes circular and smooth, sometimes irregular with broken hairs at different lengths. If you can see scalp skin through a localized area that wasn’t visible before, that’s not normal shedding. It’s a sign that something is disrupting hair growth in that specific zone, whether that’s your immune system, an infection, physical damage to the hair, or a nutritional gap.
Alopecia Areata: The Most Common Cause
The most frequent reason for sudden, round bald spots is alopecia areata, an autoimmune condition that affects roughly 2% of the global population. It happens when your immune system mistakenly targets hair follicles. Normally, hair follicles have a form of immune protection that keeps them hidden from immune cells. When that protection breaks down, certain immune cells swarm the follicle, recognize its proteins as foreign, and shut down hair production.
The result is one or more smooth, circular patches that appear suddenly, often over just a few weeks. The skin in the patch usually looks normal, with no redness or scaling. Some people feel itching or a tingling sensation before the hair falls out. Patches can appear on the scalp, beard, eyebrows, or other body hair. They sometimes overlap if multiple patches develop close together.
Alopecia areata can happen at any age, though it’s more common in children and young adults, and slightly more common in women. For many people, hair regrows on its own within months. For others, patches recur or expand, which is why getting a proper diagnosis matters.
Fungal Infections on the Scalp
A fungal infection called tinea capitis can also create bald patches, especially in children. Unlike alopecia areata, these patches come with visible clues: red, swollen skin, dry scaly rashes, and itching. One telltale sign is “black dot” tinea, where hairs break off right at the scalp surface, leaving tiny dark stubs that look like dots across the bare patch. This infection spreads through contact with infected people, animals, or contaminated objects like combs and hats, and it requires antifungal treatment to clear up.
Hair Pulling and Physical Damage
Trichotillomania, a condition involving repeated hair pulling, creates bald patches that look distinctly different from other causes. The patches tend to have irregular, geometric shapes rather than smooth circles. Under close inspection, you’ll see hairs broken at varying lengths mixed with newly growing hairs that have fine, tapered tips. The overall appearance is sometimes called “irregularly irregular,” meaning the hair loss within the patch is uneven, with some hairs spared among the broken ones.
The scalp is the most commonly affected area, though eyebrows and eyelashes can also be involved. In children, this is relatively common and often resolves with behavioral support. In adults, the pulling can become more ingrained, and the absence of eyebrows or eyelashes sometimes indicates a more persistent form.
Tight hairstyles can cause a related type of hair loss called traction alopecia, where constant pulling on the same follicles (from braids, ponytails, or extensions) gradually damages them. This typically shows up along the hairline or wherever tension is greatest.
Stress-Related Shedding
Severe physical or emotional stress can trigger a type of hair loss called telogen effluvium, though this usually causes diffuse thinning rather than distinct bald spots. The pattern is important: about three to four months after a major stressor (surgery, high fever, significant weight loss, childbirth, emotional trauma), a large number of hairs enter the resting phase simultaneously and then fall out together.
The shedding typically lasts about six months and is self-limiting once the trigger is removed. New hair begins growing back within three to six months after shedding stops, but it can take 12 to 18 months before hair volume looks noticeably restored. If you’re seeing widespread thinning rather than localized patches a few months after a stressful event, this is the likely explanation.
Nutritional Deficiencies That Affect Hair
Low levels of certain nutrients have been linked to hair loss, though the connection is stronger for some than others. In a study of 312 patients with various types of hair loss, all groups had significantly lower zinc levels compared to healthy controls. A small case series also showed that oral zinc supplementation reversed hair loss in five patients who were deficient. Vitamin D levels have been found to be lower in women experiencing hair thinning, with lower levels correlating to more severe loss.
Iron is the nutrient most commonly discussed in connection with hair loss. When iron deficiency is severe enough to cause anemia, chronic diffuse hair shedding is a recognized symptom. Below that threshold, the evidence is less clear. Dermatologists generally recommend keeping ferritin (your body’s iron storage marker) at healthy levels as a baseline, but iron supplementation alone isn’t a guaranteed fix for hair loss unless a true deficiency exists.
How Dermatologists Figure Out the Cause
A dermatologist can usually narrow down the cause of bald spots through a combination of visual examination and simple tests. The pull test involves gently tugging on a small group of hairs to see how many release easily, which helps gauge how active the shedding process is. If an infection is suspected, a scalp biopsy (scraping a small skin sample to examine under a microscope) can identify fungal organisms. Light microscopy, where hairs are examined at their base, can reveal structural problems with the hair shaft itself.
The appearance of the patch often points strongly toward a diagnosis before any testing. Smooth, round patches suggest alopecia areata. Red, scaly patches point to fungal infection. Irregular patches with hairs broken at mixed lengths raise the question of physical damage or pulling.
Treatment Options for Patchy Hair Loss
Treatment depends entirely on the cause. For alopecia areata, the most established approach for small patches is corticosteroid injections directly into the affected area, repeated every four to six weeks. Studies show strong results: in one controlled trial, 62% of patients who received injections had more than 75% regrowth after 12 weeks, compared to just 13% in the placebo group. By 24 weeks, that number rose to 87%. The main limitation is that about one in four people experience recurrence after stopping treatment.
For fungal infections, antifungal medication is essential since the infection won’t clear on its own. For trichotillomania, cognitive behavioral therapy is the primary treatment, sometimes combined with medication for underlying anxiety. For telogen effluvium, the main intervention is identifying and removing the trigger, then waiting for the natural regrowth cycle to complete.
Nutritional causes are addressed by correcting the underlying deficiency through diet changes or supplementation, though this works best when a blood test confirms a specific shortfall rather than supplementing blindly.
What the Pattern of Your Hair Loss Tells You
Pay attention to several features when examining a bald spot. A single smooth circle that appeared quickly, with no redness or flaking, most commonly points to alopecia areata. Multiple patches with scaling and itching suggest infection. Patches with hairs broken at different lengths, especially in areas your hands can reach easily, may indicate pulling. Diffuse thinning across the entire scalp, rather than localized patches, is more consistent with stress-related shedding or nutritional factors.
Also note whether the patch is growing, stable, or already showing fine regrowth. Many cases of alopecia areata begin regrowing within a few months without treatment. If a patch is expanding, developing new patches nearby, or has persisted beyond three months without change, that’s a strong reason to get a professional evaluation sooner rather than later.