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The human scalp may feel hard but it is highly sensitive. It is covered with thousands of densely packed hair follicles, each of which is attached to many nerve endings. Plus, it has the highest concentration of blood vessels, which add to the tenderness. (1)
For this reason, the scalp often gets itchy and irritated due to a variety of causes such as exposure to harsh chemicals, infections, and inflammatory conditions.
But scratching the itch will only intensify it even more and lead to further scratching. This constant friction of your nails or fingers against the thin, delicate skin of the scalp will cause tears and inflammation in the affected hair follicles.
The skin is fully capable of repairing itself. It starts by forming thick crusty scar tissue over the wound to protect it from further damage. (2)(3) This raised hardened area is known as a scab, which tends to get drier and pricklier as the underlying wound begins to heal.
New skin cells replace the dry scar tissue, which gradually loosens and sloughs off to reveal new healed skin underneath. However, many people cannot stop themselves from scratching or picking at the itchy scabs.
The friction from their sharp nails damages the new skin cells produced by the body to repair the wound, thereby setting back the healing process. Also, scratching and picking at the scabs can transfer germs to the wounded area, causing an infection.
What Causes Scabs on the Scalp?
Some common causes that make your scalp itchy and lead to the formation of scalp scabs include:
- Scalp sensitivity – It is characterized by prickling, tingling, or burning sensation. (4)
- Seborrheic dermatitis – It is an inflammatory condition characterized by itchy, scaly patches on the scalp along with flaking or dandruff.
- Scalp psoriasis – It is a chronic inflammatory skin condition that leads to the formation of raised patches of itchy, scaly skin that tends to rupture, bleed, and scab over. (5)
- Lichen planopilaris (LPP) – It is an inflammatory condition that leads to the formation of tiny, red papules on the scalp that may scab over. (6)
- Tinea capitis or ringworm of the scalp – It is a fungal infection that causes itchy, crusty rashes and pustular blisters on the scalp. (7)
- Scabies – It is a common skin infestation caused by minuscule mites called Sarcoptes scabiei. They dig into the skin to deposit their fecal matter, which triggers an inflammatory response by the body. The inflammation manifests in the form of small itchy bumps and blisters on the skin. (8)
- Head lice – They are tiny parasites that feed on the blood from the scalp and cause inflammation. The scalp inflammation leads to intense itching. (9)
- Shingles – It is a viral infection that causes a painful skin rash that often blisters and scabs over. (10)
- Any injury or blunt force trauma to the scalp – It can rupture the skin and underlying tissue. This tear is known as a laceration, and it tends to scab over as it heals. (3)
- Excessive exposure to certain irritants – Excessive exposure to water, chemical-laden hair products, heating tools such as a blow-dryer, and environmental irritants such as sunlight, dust, and pollutants can strip away the natural lipids from your scalp to render it dry, itchy, and irritated. (2)
- Stress – It can flare up certain inflammatory conditions that can make your scalp itchy, scaly, and prone to scabbing. Stress also hinders wound healing and thereby extends the time it takes for the scabs to go away. (2)
Symptoms of Scabs on the Scalp
Scalp scabs usually have the following characteristics:
- They have a dry, rough, crusty texture.
- They are slightly raised above the surrounding skin.
- They can have a yellow, red, brown, or black crust.
- In rare cases, the scab may ooze green pus, which is a sign of infection.
- They itch a lot. (1)
- There may be a collection of tiny scabs joined together or smaller scabs spread across your scalp.
Treatment for Scalp Scabs
Commonly used medical interventions for treating and preventing scab formation on the scalp are:
- Topical corticosteroids – These are often prescribed to manage the scalp discomfort caused by psoriasis and dermatitis that lead to scab formation. They work by reducing the underlying inflammation to make your scalp itch less, and they are available in the form of medicated shampoos, foams, and serums.
- Antihistamine pills – These are prescribed if the scalp inflammation and itching are caused by an allergic reaction.
- Antidepressant/psychotherapy – This is recommended if stress is triggering the scalp inflammation and itching leading to scab formation.
- Light therapy or phototherapy – This uses specific frequencies of light to treat various scalp conditions that cause scabbing. (2)
Diagnosing Scalp Scabs
Scalp scabs usually form over open sores or tears in the skin, but you may need a proper diagnosis if they occur repeatedly or without a discernible reason. This usually involves the following steps:
- Medical history of the patient
- Physical examination of the scalp
- Lab tests at the doctor’s discretion
When to See a Doctor
Scalp scabs are rarely a cause of concern and usually don’t require medical treatment. However, you must consult your doctor in the following cases, which can point to a more serious underlying problem:
- If you repeatedly get painful and itchy sores on your scalp
- If the scalp scab becomes very painful, tender, swollen, and warm to the touch and starts oozing discharge, all of which are signs of infection
- If the sore on your scalp fails to scab over and heal within 4–8 weeks
- If you experience pain and swelling in the scalp along with scab formation
Scabs generally resolve on their own within 7–14 days, but the healing time can vary depending on the location, size, and depth of the wound they form over. The general health of the patient also plays a role in determining the duration of the healing process.
Scabs formed due to minor tears in the skin caused by scratching will go away faster than those that form on skin lacerations or inflammatory rashes.