A localized, painful spot on the scalp is a common symptom that can range from simple irritation to underlying nerve issues. This specific tenderness, often triggered by non-painful actions like brushing hair or resting one’s head, is medically defined as scalp allodynia. Allodynia is the experience of pain from a stimulus that should not normally provoke a painful response, indicating heightened sensitivity in the sensory nerve pathways. Pinpointing the origin of this isolated discomfort is the initial step toward finding relief.
Causes Related to Hair Structure and Follicles
The most frequent causes of localized tenderness are related to physical stress on the hair follicles, which are surrounded by sensory nerves. Wearing tight hairstyles, such as high ponytails, braids, or hair extensions, creates mechanical tension that pulls on the hair shaft and irritates the follicle root. This constant tension causes inflammation around the follicular opening, resulting in soreness that is relieved when the hair is let down.
Folliculitis is the inflammation or infection of one or more hair follicles, typically caused by bacteria or fungus. It appears as small, red, or pus-filled bumps that resemble acne and can be intensely painful or tender to the touch. The infection causes inflammation and swelling within the follicle, making the localized area hypersensitive to movement or pressure.
The skin may also react to external substances in a specific area, leading to contact dermatitis. This allergic or irritant reaction can be triggered by a new shampoo, conditioner, hair dye, or styling product. The resulting inflammation, redness, and itching in that localized patch can cause significant soreness and tenderness.
Pain Originating from Nerves and Headaches
When the scalp is tender but shows no visible signs of rash, infection, or trauma, the pain is often neurological. Occipital neuralgia is a condition where the occipital nerves, which run from the neck up to the scalp, become irritated, compressed, or inflamed. This irritation causes a distinct, localized pain described as sharp, shooting, or electric-shock like, starting at the base of the skull and radiating over the scalp, usually on one side.
This nerve-based pain can make simple actions like lying on a pillow or brushing the hair intensely painful. The nerve entrapment often occurs due to muscle tightness in the neck or a prior injury, causing the affected area to become hypersensitive. Occipital neuralgia is sometimes confused with migraine, as both can involve localized scalp tenderness and pain that radiates toward the forehead or behind the eye.
Referred pain from severe headaches, particularly migraines, is another neurological cause of single-spot tenderness. This occurs due to central sensitization, a process where the nervous system becomes highly responsive to stimuli. During a migraine attack, the nerves can become hypersensitive, causing light touch or movement, such as wearing glasses or a ponytail, to result in localized pain in the scalp.
Localized Skin Infections and Inflammatory Conditions
Specific medical conditions that create a bump or lesion can cause a precise spot of pain. A common example is an inflamed pilar cyst, a slow-growing, benign lump filled with keratin that forms around a hair follicle. While usually painless, if the cyst ruptures, is injured, or becomes infected, it can lead to acute localized pain, swelling, and redness.
Localized infections may arise from the reactivation of the varicella-zoster virus, causing herpes zoster, commonly known as shingles. Shingles on the scalp typically presents with a burning, tingling, or sharp pain that precedes the appearance of a rash. The rash consists of clusters of tiny, fluid-filled blisters that form along the path of a single nerve (a dermatome) and usually appear on only one side of the head.
Chronic inflammatory skin conditions like localized severe seborrheic dermatitis or psoriasis can manifest as a single, painful patch. Psoriasis causes thick, scaly, inflamed plaques that are often sore and itchy, while severe seborrheic dermatitis leads to persistent, flaky, and greasy patches. These conditions create localized inflammation that irritates the underlying nerve endings, causing the area to be painful to the touch.