A severe sunburn on the scalp can lead to hair loss. Sunburn is a form of acute inflammatory trauma affecting the scalp skin. Intense exposure to ultraviolet (UV) radiation triggers a biological stress response. While the hair loss is not immediate, severe skin damage disrupts the natural cycle of hair growth. This disruption sets the stage for a temporary increase in hair shedding weeks or months after the initial burn heals.
How Sunburn Affects the Hair Follicle
The scalp skin contains hair follicles embedded in the dermis, making them vulnerable to trauma. UV radiation from a severe sunburn directly damages the cellular structure of the scalp, including keratinocytes and underlying dermal tissue. This damage initiates a robust inflammatory cascade as the body attempts to repair the injury.
The body responds by releasing pro-inflammatory cytokines. These signaling molecules act as messengers, signaling a state of emergency throughout the affected area. This biochemical alarm disrupts the normal growth cycle of the hair follicles. Follicles in the active growth phase (anagen) receive this premature signal to shut down.
The intense inflammation halts the cellular division and metabolic activity required for hair production. This premature exit from the active growth phase pushes a large number of follicles into the resting phase (telogen). In severe cases, UV radiation can penetrate deeply enough to damage the epidermal stem cells or the dermal papilla, which regulates hair growth. Damage to these structures can lead to localized follicle disruption.
Understanding Acute Hair Shedding
Hair loss resulting from a severe inflammatory event like a sunburn is a temporary condition called acute telogen effluvium (TE). This hair shedding occurs when sudden physiological stress causes an abnormally high percentage of growing hairs to prematurely enter the resting phase. Normally, only 10 to 15 percent of scalp hairs are in the telogen phase at any given time.
The shedding does not occur instantly after the burn, which is why the connection can be missed. There is a typical delay of two to four months between the sunburn event and the onset of hair fall. This lag represents the time it takes for the hair shaft, which has stopped growing, to be fully extruded from the follicle. The loss is usually diffuse across the scalp.
Once the scalp has fully healed and inflammatory signals subside, the hair cycle resets. Telogen effluvium is considered non-scarring, meaning the hair follicles are not destroyed. The shed hairs will typically begin to regrow normally. Full recovery is generally expected within several months after the shedding peaks.
Treating a Sunburnt Scalp
Immediate treatment focuses on reducing acute inflammation and pain to minimize further follicle disruption. Applying cool, moist compresses or taking a cool shower provides instant relief by drawing heat away from the damaged skin. It is important to avoid using ice directly on the scalp, as this can cause additional tissue damage.
Anti-inflammatory agents help soothe the burn and promote healing. Over-the-counter preparations like pure aloe vera gel, which has cooling and anti-inflammatory properties, should be applied gently. For pain management and to reduce systemic inflammation, a nonsteroidal anti-inflammatory drug (NSAID) can be taken as directed. Using a mild, sulfate-free shampoo is advisable to prevent further irritation.
The sunburnt skin may begin to peel as part of the healing process. Resist the urge to pick or scratch at the flaking skin, as removing damaged skin prematurely can exacerbate trauma to the superficial layers. Gentle handling and moisturizing with products containing ingredients like aloe or soy aid in the natural recovery of the skin barrier.
Protecting the Scalp from UV Exposure
Prevention is the most effective strategy for safeguarding the scalp and hair follicles from UV damage. Physical barriers offer the most reliable defense against intense solar radiation. Wearing a wide-brimmed hat or a scarf provides immediate coverage, blocking the sun’s rays entirely.
For areas not covered by a hat, specialized sunscreens formulated for the scalp should be used. These products often come in lightweight spray, mist, or powder forms to avoid making the hair overly greasy. A broad-spectrum sunscreen with an SPF of 30 or higher should be applied to the part line, receding areas, and any exposed scalp skin.
Even a full head of hair may not offer complete protection, as UV rays can penetrate through the strands, especially where the hair is parted or thinned. Sunscreen should be reapplied every two hours, or immediately after swimming or excessive sweating, to maintain efficacy. Limiting direct sun exposure during peak hours, typically between 10 a.m. and 4 p.m., is an additional measure to reduce the risk of a severe scalp burn.