A bald spot is an area of the scalp (or sometimes the body) where hair has stopped growing or has fallen out, leaving smooth or thinning skin visible underneath. Most bald spots fall into one of a few categories: an autoimmune reaction attacking hair follicles, genetic pattern baldness, a fungal scalp infection, or physical damage from tight hairstyles. The cause determines whether the spot will fill back in on its own, need treatment, or become permanent.
Why Bald Spots Form
Hair follicles cycle through growth, rest, and shedding phases. A bald spot appears when something disrupts that cycle or damages the follicles themselves. The disruption can be internal, like an immune system malfunction or a hormone shift, or external, like a fungal infection or repeated physical pulling on the hair. In some cases, the follicles simply shrink over time until the hairs they produce are too fine and short to be visible.
Alopecia Areata: The Coin-Sized Patch
The most recognized type of bald spot is alopecia areata, where the immune system mistakenly attacks hair follicles and causes inflammation. Specialized immune cells infiltrate the follicle and trigger a self-reinforcing cycle: the inflammation causes the follicle to lose its normal immune protection, which attracts more immune cells, which causes more inflammation. The result is one or more smooth, round patches roughly the size of a coin.
About 2% of people will develop alopecia areata at some point in their lives, and it most commonly shows up in young adults. The good news is that for people with small patches covering less than 25% of the scalp, spontaneous regrowth happens in roughly 68% of cases. Overall, 30 to 50% of people with patchy alopecia areata see their hair return within the first 6 to 12 months without any treatment, and up to 66% experience complete resolution within five years.
Under close examination, alopecia areata patches have distinctive features: tiny yellow dots across the bare skin, “exclamation mark” hairs (short hairs that taper to a thinner base), and fine, pale vellus hairs beginning to regrow. These signs help distinguish it from other causes of hair loss.
Pattern Baldness
The most common cause of hair loss overall is androgenetic alopecia, or pattern baldness. In men, this typically shows up as a receding hairline and bald spots on the crown of the head. In women, it appears as gradual thinning along the part line and top of the scalp rather than distinct bare patches. It’s driven by genetics and hormones, runs in families, and progresses slowly over years as follicles miniaturize and produce increasingly thinner hairs.
Pattern baldness doesn’t resolve on its own, but it responds to treatment. Topical minoxidil (available over the counter in 2% and 5% solutions) is the most widely used option and is applied directly to the scalp. Low-dose oral minoxidil has also shown results: one trial found that 5 mg daily significantly improved hair growth in men, while a study of women saw hair density improve by 23 to 38% across different scalp areas after about six months on a lower dose.
Fungal Infections
Ringworm of the scalp (tinea capitis) is a fungal infection that creates bald patches, especially in children. Unlike the smooth patches of alopecia areata, fungal bald spots tend to look scaly, inflamed, or crusty. The remaining hairs in the patch often break off in characteristic shapes: comma-shaped, corkscrew, or zigzag hairs are telltale signs of a fungal cause. You may also see black dots where hairs have snapped off at the scalp surface. The area is often itchy or tender.
Fungal bald spots require antifungal treatment to clear. They won’t resolve on their own, but the hair typically grows back fully once the infection is treated.
Traction Alopecia: Damage From Tight Styles
Bald spots can also result from hairstyles that pull on the hair over long periods. Braids, cornrows, tight ponytails, weaves, and dreadlocks all place mechanical stress on the follicles, particularly along the hairline and temples. Chemical relaxers and heat styling add to the damage. This type of hair loss, called traction alopecia, is also seen in ballet dancers, military personnel, and anyone whose occupation or cultural practices involve tightly styled hair.
The critical thing to understand is that traction alopecia follows a two-phase pattern. In the early stage, the damage is reversible. If you stop the pulling, the hair grows back completely. But if the tension continues over months or years, the follicles shrink, scar tissue forms around them, and the stem cells at the base of the follicle are permanently destroyed. At that point, the bald spot becomes permanent. Catching it early is the difference between full recovery and irreversible loss.
Nutritional Deficiencies and Hair Loss
Low levels of iron and vitamin D are linked to increased hair shedding, though they more commonly cause diffuse thinning than distinct bald patches. In one study, people with hair loss had average iron storage levels (measured as ferritin) of about 15 ng/ml, compared to 25 ng/ml in people without hair loss. Their vitamin D levels averaged 14 ng/ml, well below the normal threshold of 20 ng/ml. Zinc levels showed a weaker connection overall, though people with the lowest zinc values were more likely to have alopecia areata or excessive shedding.
If you’re losing hair and your diet is limited, or you have risk factors for nutritional deficiency (heavy periods, a vegan diet, limited sun exposure), a blood test can identify whether low iron, vitamin D, or zinc might be contributing.
How Bald Spots Are Diagnosed
A dermatologist can usually identify the cause of a bald spot through a visual exam and a few simple tests. The pull test involves gently tugging on a small group of hairs to see how many come out, which indicates whether hair is actively shedding. Dermoscopy, a magnified examination of the scalp surface, reveals specific hair and follicle features that point to a diagnosis. For example, exclamation mark hairs suggest alopecia areata, while comma-shaped hairs point to a fungal infection.
In cases where the cause isn’t clear from the surface, a small scalp biopsy or lab work may be needed. Blood tests can check for iron, vitamin D, thyroid function, and markers of autoimmune activity.
Treatment Options by Cause
Treatment depends entirely on what’s causing the bald spot. For alopecia areata, options include corticosteroid injections into the patch to suppress the local immune response, topical treatments applied to the scalp, and newer oral medications. In 2022, the FDA approved baricitinib, a pill that works by blocking the specific immune signaling pathway (called JAK-STAT) that drives the follicle attack. JAK inhibitors have shown strong results for alopecia areata, particularly in more extensive cases.
For pattern baldness, minoxidil and prescription options that block the hormonal pathway behind follicle miniaturization are the standard approaches. Fungal infections require antifungal medication, typically taken orally for several weeks. Traction alopecia is treated by removing the source of tension. If scarring has already occurred, the options narrow considerably, and some people pursue hair transplant procedures for permanent patches.
For nutritional causes, correcting the underlying deficiency through supplements or dietary changes can slow or reverse the shedding, though regrowth takes months because hair grows slowly, roughly half an inch per month.