Dandruff vs dry scalp: Differences, similarities, and treatment

Dry scalp is an ailment caused by a lack of moisture in the skin of the head, while dandruff is brought on by an excess of oil production and an overgrowth of Malassezia yeast on the scalp. Although they are two distinct diseases, dandruff and dry scalp share similar primary symptoms, which include falling flakes and an itchy scalp. But, despite their similarities in symptoms, dry scalp and dandruff can be differentiated from each other as follows: Flakes from dandruff are oily, large, and white with a yellowish tinge, while flakes from dry scalp are smaller, dry, and whiter. Dry scalp results in frizzy and dull-looking hair due to a lack of sufficient oil to moisten it, whereas hair with dandruff may seem oily, greasy, and flaky at the same time.

In addition, dry scalp causes other parts of the body, such as arms and legs, to also be dry, but dandruff is restricted only to the scalp of the head. A useful method to determine if you have dandruff or a dry scalp is to apply a mild moisturizer to your scalp before bed. If you have a dry scalp, the flakes should go away when you take a shower the following morning. If the flakes do not go away, then you have dandruff. Finally, neither dry scalp nor dandruff are contagious. This means you cannot pass it on to someone else through person-to-person contact. 

What causes a dry scalp?

A dry scalp is caused by a lack of moisture on the scalp of the head. This results in the skin on the scalp becoming irritated, itchy, and starting to flake off. People with dry scalps also experience dryness in other parts of their body, such as their arms and legs. Several reasons exist why your hair scalp loses too much water or moisture and becomes dry. Reasons for a dry scalp include:

• Contact Dermatitis. This results from a reaction to products you apply to your scalp, including shampoo, styling gel, or hairspray. Many of these products dry out your hair by stripping it of its natural oils, which can leave your scalp irritated.
• Cold weather or a low-humidity environment causes your scalp to become dry.
• Age. The skin dries out as you get older.
• Hormonal imbalance. For example, a drop in estrogen and progesterone causes a decrease in skin moisture and contributes to a dry scalp.
• Medication side effects. Several medication types cause dry scalps as a side effect. This includes acne medications, retinoids, antihistamines, blood pressure medications, cholesterol-lowering medications, and chemotherapy drugs.
• Psoriasis. Psoriasis is a chronic or long-lasting disease that causes your skin cells to multiply too fast. Consequently, patches of skin become scaly and inflamed. Psoriasis can be triggered by several factors, including infection, injuries, medications, alcohol, smoking, or an overreaction of the immune system.
• Scalp ringworm (Tinea capitis). This is a fungal infection that causes itchy, scaly, and bald patches on the head. It is very contagious and can easily be passed on through direct person-to-person or person-to-animal contact.
• Actinic keratosis, or solar keratosis. This is an abnormal growth of cells on the scalp of the head because of unprotected sun exposure. It is also common with people who are 50 years of age or older.

How do you prevent dry scalps?

Dry, scaly, and itchy scalps can be prevented in several ways. This includes:

• Washing your hair less frequently to avoid washing away the oil produced by your scalp. Too little washing can instead cause a dry scalp. So, wash your hair every 3 to 5 days, or once per week. However, how frequently you wash your hair will depend on your hair type. Seek professional advice if needed.
• Use a gentle and moisturizing shampoo.
• Avoid using products containing irritants or harsh chemicals such as sulfates, bleach, parabens, alcohols, formaldehydes, and synthetic fragrances. These chemicals dry out your scalp. Instead, search for chemicals with rich and nourishing ingredients such as keratin, omega-3, omega-6, hyaluronic acid, aloe vera, and vitamin B3, which can restore moisture to your scalp.
• Drink water more frequently. Drink at least 2.5 liters of water per day to stay fully hydrated.
• Use a humidifier to add humidity to your home if needed.
• Avoid smoking!
• Manage your stress level. Stress can weaken your immune system against naturally existing microbes in the scalp or cause the release of inflammatory chemicals, which cause dryness and flakiness of the scalp.

How to treat a dry scalp

Because several factors can cause dry scalp, treatment will depend on the cause of the condition.

Treating dry scalp caused by hair products or contact dermititis

If dry scalp is due to the use of hair products or contact dermatitis, then treat as  follows:

• Rinse out any hair products, including shampoo, thoroughly. Products left on your scalp after showering may cause irritation.
• If thorough rinsing does not work, then stop using the product and switch to a more gentle and non-medicated alternative. A specialized shampoo for dry scalps helps relieve the dryness and flakes on the scalp.
• Restrict the number of times you shampoo your hair per week and opt for a co-wash.
• If you face difficulties finding the right product for your hair, then shift to natural and DIY alternatives such as a hair mask with moisturizing ingredients or any combination of milk, honey, coconut oil, and avocado. Milk, for example, is rich in lipids and proteins, which help strengthen the hair, while calcium in milk helps promote hair growth.

Treating dry scalp caused by aging, cold weather, or a low-humidity environment

If your dry scalp is due to aging, cold weather, or a low-humidity environment, then treat it as follows:

• Use a humidifier or dehumidifier to regulate the climate in your home.
• Increase your water intake to stay hydrated.
• Treat your hair with a humectant such as aloe vera gel or hyaluronic acid, and cover the hydration with a light-weight oil such as argan or jojoba before bedtime.
• Make use of a gentle, moisturizing, and non-medicated shampoo. Also, condition your hair after shampooing.
• Avoid heat styling or using very hot water.

Treating dry scalp caused by psoriasis, tinea capitis, or actinic keratosis

Your dry scalp may be due to a more serious condition such as psoriasis, tinea capitis, or actinic keratosis, in which case changing shampoo, using home remedies, or over-the-counter medications won’t work.  However, a healthcare provider or dermatologist can help diagnose the cause and provide adequate treatment for your dry scalp. Besides, contact a dermatologist immediately if your scalp is constantly itching, develops red rashes, or becomes swollen, warm, or painful to the touch.

What causes dandruff?

Seborrheic dermatitis is a chronic form of eczema that affects areas of the body that are rich in oil-producing (sebaceous) glands, such as the upper back, chest, nose, and scalp. The exact cause of seborrheic dermatitis is not known but may be due to excess oil in the skin, a problem in the immune system, or an overgrowth of the yeast Malassezia. It causes lots of symptoms, including dryness, flakiness, rashes, peeling, or redness. Cradle cap is a term used to describe seborrheic dermatitis of the scalp in infants.

Dandruff is a mild form of seborrheic dermatitis, and unlike seborrheic dermatitis, it does not spread to other parts of the body, such as behind the ears, nose, upper lip, eyelids, eyebrows, and upper chest. Dandruffs are restricted only to the scalp of the head.

Dandruff is caused by the excessive buildup of dead skin cells, which then begin to flake off. Symptoms include flakiness and itching of the scalp, but no redness or scabbing. Seborrheic dermatitis and severe dandruff are linked medical conditions. You may have seborrheic dermatitis if you experience redness along with scaling on your scalp or if the redness and flaking migrate to your cheeks, eyebrows, or nose sides.

Dandruff gets worse during the fall and winter and improves in the summer. Also, dandruff can get worse when you are stressed, anxious, or tensed.

In addition to an overgrowth of Malassezia yeast, excess production of skin oil, and a compromised or weak immune system, other factors that favor the growth of dandruff include aging, hormonal imbalance, stress, an underlying medical condition, nutritional deficiency, side effects of certain medications, or environmental changes.

How do you prevent dandruff?

Dandruffs can be prevented in any of the following ways:

• Daily shampooing with a gentle, moisturizing, and non-medicated shampoo to reduce excess oil on the scalp.
• Use an over-the-counter dandruff shampoo. However, talk to your doctor about how frequently you might need to use it.
• Every day, take a few minutes to enjoy the sun outside. Evidence suggests that exposure to ultraviolet (UV) light can help manage dandruff. However, excessive sun exposure raises the risk of skin cancer; therefore, you should avoid too much or dangerous exposure.
• Increase your intake of Omega-3 and zinc. Fish, sea foods, nuts and seeds are very rich in Omega-3 and zinc.
• Minimize the use of hair products especially medicated hair products or hair products containing harsh chemicals such as alcohol, bleach, or sulphates.
• Avoid stress and anxiety!
• Cut down on sugary or spicy foods. They promote the growth of yeast and can weaken the immune system.
• Eat healthy and exercise regularly. This will also help strengthen your immune system.

How to treat dandruffs

Dandruff is a chronic condition that cannot be permanently cured. However, the signs and symptoms of dandruff can be managed or prevented through frequently use of anti-dandruff products, maintaining a healthy scalp, and eating healthy. Unlike dandruff, dry scalp can permanently be cured using specialized shampoos.

To treat mild dandruff, simply wash your hair regularly with a gentle and moisturizing shampoo. This will lower the amount of oil on your scalp. However, for severe cases of dandruffs whereby normal shampoo does not work, then use anti-dandruff or medicated shampoo.

If your dandruff persists or gets worse with no improvement in signs and symptoms after using an anti-dandruff shampoo for at least a month, or the skin on your scalp looks red and swollen, then see a dermatologist. Also see a doctor if your experience redness and flakiness on areas of your body other than the scalp. Other conditions, such as eczema or psoriasis, can cause flaky skin on your scalp. In the event of a more severe case of dandruff, the doctor can prescribe a stronger shampoo, a topical steroid, or a topical antifungal.

Types of shampoo used to treat dandruff

A shampoo, whether regular, over-the-counter or prescribed, can be used to treat dandruff if it contains any of the following medications:

• Zinc Pyrithione (Head and Shoulders, Jason Dandruff Relief 2 in 1, ZNP). This is an antifungal medication that kills the fungus on your scalp that causes itching and flaking. Shampoos containing Zinc Pyrithione are sufficiently gentle to allow for everyday use.
• Selenium sulfide (Selsun Blue). This reduces the fungus on your scalp that causes flakiness and prevents too many skin cells from dying off. Shampoo with selenium sulfide can change your hair color. So, speak to your healthcare provider before using this type of shampoo if you have blond or gray hair or if you are dyeing your hair.
• Ketoconazole (Nizoral). It is an anti-fungi drug that kills the fungus that causes dandruff. You can obtain it over-the-counter or on prescription.
• Salicylic acid (Neutrogena T/Sal). It gets rid of excess scalp scales before they flake. Salicylic acid may also worsen flaking and dry up your skin.
• Coal tar (Neutrogena T/Gel). Tar-based shampoos slows down the growth and shedding of skin cells on your scalp. It has both antifungal and antibiotic properties. If you have gray, blond, or white hair, a tar-based shampoo can change the color of your hair. However, tar-based treatment can also make the scalp extra sensitive to sunlight. Therefore, protect your scalp when stepping under the sun.

You might have to try 2 or 3 different anti-dandruff shampoo to figure out which one works best for you. See a doctor or pharmacist for assistance if you’re unsure about the type of shampoo to use or how often to use it. After your dandruff gets better, reduce the number of days you use the shampoo to avoid drying your scalp.

Summary on dandruff vs dry scalp