A bald spot on the top of your head is most commonly caused by androgenetic alopecia, also known as pattern hair loss. This is the single most common reason for thinning or balding at the crown in both men and women. But it’s not the only possibility. Autoimmune conditions, scarring disorders, nutritional deficiencies, and even tight hairstyles can all produce a bald spot in that area, and each one looks and behaves differently.
Pattern Hair Loss: The Most Likely Cause
Androgenetic alopecia affects the crown because hair follicles in that area are genetically sensitive to a hormone called DHT (a byproduct of testosterone). When DHT binds to receptors on those follicles, it shortens the growth cycle. Each new hair comes in thinner and shorter than the last, and eventually the follicle stops producing visible hair altogether. Variations in a gene called AR can make your follicle receptors respond more aggressively to DHT, which is why this type of hair loss runs in families.
In men, this typically shows up as thinning at the crown that expands outward over time, often alongside a receding hairline that forms an “M” shape. In women, the pattern is different. Hair thins along the center part first, creating a widening gap, and then spreads outward across the top of the scalp. Women rarely lose their frontal hairline the way men do. The Sinclair scale, used to grade female pattern hair loss, tracks this progression from a slightly wider part line all the way to visible bald patches near the front of the head.
The key feature of pattern hair loss is that it’s gradual. If your bald spot appeared slowly over months or years, and the surrounding hair looks thinner rather than completely absent, this is the most probable explanation.
Alopecia Areata: Sudden, Smooth Patches
If your bald spot appeared quickly and is roughly the size of a quarter, with smooth skin underneath and no redness or flaking, alopecia areata is a strong possibility. This is an autoimmune condition where your immune system mistakenly attacks hair follicles, causing inflammation that shuts down hair production in a localized area. Both genetic and environmental factors contribute, though researchers still don’t fully understand what triggers the attack.
A telltale sign is “exclamation point” hairs around the edges of the patch. These are short, broken strands that are narrower at the base than the tip. Some people also notice tingling, burning, or itching on the scalp just before the hair falls out. Unlike pattern hair loss, alopecia areata can strike at any age and often appears suddenly, sometimes over just a few weeks. The good news is that in many cases, hair does regrow on its own, though recurrence is common.
Scarring Alopecia and CCCA
Some types of hair loss permanently destroy the follicle and replace it with scar tissue. One form that specifically targets the top of the head is central centrifugal cicatricial alopecia (CCCA), which most often affects middle-aged Black women. It begins in the center of the scalp and spreads outward.
The scalp in affected areas often looks shiny and smooth. Before noticeable hair loss appears, you might feel tiny bumps or notice scaly, crusty patches. Intense itching or pain on the scalp is common. This condition requires early treatment because once scar tissue forms, those follicles cannot produce hair again. If your bald spot has a shiny, smooth surface and your scalp feels tender or irritated, this is worth investigating promptly.
Tight Hairstyles and Traction Alopecia
Repeated pulling on the hair from tight cornrows, braids, buns, ponytails, extensions, or weaves can damage follicles over time. This is called traction alopecia, and it can affect the crown if that’s where the tension concentrates. Even the constant rubbing of a hat or head covering can contribute, especially if your hair is pulled back tightly underneath.
Early warning signs include broken hairs, a receding hairline, and small patches of thinning where the tension is greatest. If caught early, changing your hairstyle allows regrowth. But when traction alopecia progresses to the point where you see shiny, bald skin, the damage is permanent.
Nutritional Deficiencies That Thin Your Hair
Low iron and low vitamin D are both linked to hair thinning, particularly in women. In one study of women with pattern hair loss, 89% had deficient or insufficient vitamin D levels, and 74% had low iron stores. Clinically, ferritin (stored iron) below 30 µg/L is considered very low, and vitamin D below 20 ng/ml is classified as deficient. Both are correctable, and hair often improves once levels are restored, though it can take several months to see a difference.
These deficiencies don’t always cause a distinct bald spot on their own, but they can accelerate thinning that’s already underway from another cause, making a developing bald spot more noticeable faster than it otherwise would be.
What a Dermatologist Visit Looks Like
If you’re unsure what’s causing your bald spot, a dermatologist can usually narrow it down in a single visit. They’ll start by asking when the hair loss began, whether it happened gradually or suddenly, what hairstyles you typically wear, and whether hair loss runs in your family. Then they’ll examine your scalp for inflammation, redness, sores, or scarring, and look closely at the pattern of loss and whether hairs are breaking or thinning.
A pull test involves grasping about 40 strands and tugging gently. If six or more come out, that signals active shedding. A tug test checks whether strands snap in the middle, indicating brittleness. Your doctor may also use a magnifying tool called a folliscope, which can enlarge the view of your scalp up to 100 times to assess follicle health and hair diameter.
Blood tests are common, particularly to check ferritin, thyroid function, and vitamin D. If scarring alopecia is suspected, or if the pattern doesn’t fit a straightforward diagnosis, a scalp biopsy may be recommended. This is a quick in-office procedure using a pencil-sized punch tool to remove a small tissue sample, which is then examined under a microscope. A biopsy can distinguish between scarring and non-scarring hair loss, identify specific inflammatory patterns, and rule out fungal infections or autoimmune conditions like lupus.
Treatment Options for Crown Hair Loss
For androgenetic alopecia, topical minoxidil (applied directly to the scalp) is the most widely used first-line treatment. In a study evaluating 5% minoxidil over one year, 62% of men saw their balding area shrink, while 35% stayed the same and only 3% got worse. When patients rated regrowth quality, about 16% found it very effective and another 48% found it effective. Results typically start showing around the four-month mark, and consistent daily use is required to maintain them.
For men, an oral medication that blocks DHT production can also slow or reverse crown thinning. Studies show progressive improvement over the first two years of use, with the best results at the vertex specifically. This medication is not used in women of childbearing age due to risks during pregnancy.
Alopecia areata is treated differently, often with anti-inflammatory approaches ranging from topical treatments to newer oral medications that target the specific immune pathways involved. CCCA and other scarring alopecias focus on stopping inflammation early to preserve remaining follicles, since lost ones cannot be recovered. Traction alopecia requires eliminating the source of tension. Nutritional deficiencies call for supplementation guided by blood work.
The type of treatment that will work for you depends entirely on what’s causing the bald spot, which is why getting the right diagnosis matters more than jumping to a product off the shelf. A bald spot that appeared suddenly, feels painful or itchy, or shows signs of scarring warrants faster attention than one that’s been slowly developing over years.