Itchy scalp: the reasons behind the constant itch

An itchy scalp is usually one of four things: dandruff, ringworm, lice, or a skin disease that happens to sit on the scalp. They look similar, they are treated completely differently, and the wrong treatment makes two of them worse.

The four common ones

• Seborrhoeic dermatitis, which is what most people call dandruff: greasy yellowish flakes, itch, redness at the hairline, behind the ears, in the eyebrows and either side of the nose. It comes and goes with winter, stress and sleep.
• Scalp psoriasis: thick silvery scale in well-defined patches, often past the hairline onto the forehead and behind the ears, with pitting in the nails and plaques on the elbows or knees. It is dry rather than greasy, and it does not respond to anti-dandruff treatment.
• Ringworm of the scalp, tinea capitis: patchy scaling with hair broken off short, often a bald area, commonly in a child, sometimes a boggy tender lump called a kerion. It needs oral antifungal medicine for weeks. Creams alone do not reach inside the hair follicle, and a kerion treated late can leave permanent hair loss.
• Head lice: itch that is worst at the back of the head and the nape, with nits firmly attached to the hair shaft a centimetre or two from the root, and often other children at home or school with the same complaint. It is not a sign of poor hygiene, and it is not shameful, but it will not settle until everyone is treated at once.

The others worth knowing

• Contact dermatitis from a hair dye, a serum, a shampoo, a relaxer or a perm. The itch starts a day or two after the product, the hairline and the back of the neck are worst, and the answer is stopping the product rather than treating the rash.
• Folliculitis: small itchy or tender pimples around the hair roots, sometimes after oiling, a helmet, or a close shave of the head.
• Scabies, which itches everywhere at night, classically in the finger webs and the waistline as well, and which affects the whole household.
• Atopic eczema, in a person with a history of asthma, hay fever or childhood eczema.
• Fungal infection spread from a pet, from a shared comb, from a gym, or from a salon towel. Ringworm in adults has become markedly more common in Indian cities, and much of it is the result of what was applied before it was diagnosed.
• Itching with no rash at all, which can come from dry skin in winter, and more rarely from anaemia, kidney disease, thyroid disease, liver and bile-duct disease, or a blood disorder. Persistent generalised itch without a visible cause is a blood-test question.

The oiling question, said plainly

• Daily hair oiling is a genuine habit in most Indian households, and for seborrhoeic dermatitis it makes things worse. The yeast involved feeds on the lipids in the oil, so the treatment that feels most logical is the one that fuels the problem.
• Oil also glues flakes to the scalp, traps heat, and can block follicles into folliculitis.
• It is not the cause of dandruff, and stopping it for a month is often the most informative thing a person can do.
• Where oil is used, it goes on the lengths rather than the scalp, in a small amount, and is washed out properly.
• The same caution applies to heavy creams and to leaving a medicated preparation under oil overnight.

Red flags that need a doctor rather than a shampoo

• A patch where the hair has broken off or disappeared. That is ringworm or scarring until proved otherwise, and scarring loss is permanent if it is not treated early.
• A boggy, tender, discharging lump on the scalp, with or without fever and swollen glands at the back of the head. A kerion, and it needs oral treatment now.
• Thick scale with pus, crusting, or a spreading redness, which means bacterial infection on top of whatever caused the itch.
• Itch so severe that sleep is broken most nights for weeks, or with swollen glands, weight loss, night sweats, or itching elsewhere on the body.
• A scalp lesion that bleeds, scabs, changes colour, or does not heal in three weeks, particularly in a bald head with years of sun behind it.
• Sudden patchy hair loss without scale or itch, which is a different condition with a different pathway.
• Itching with a rash over the body, or with mouth or eye involvement, which is not a scalp problem at all.

What we ask and what we look at

• How long, where it started, what has been applied, and whether anyone else at home itches.
• The products, in order: shampoo, oil, dye, serum, and any medicated cream somebody else recommended. A steroid cream applied to ringworm produces tinea incognito, which looks better, spreads further, and takes longer to clear.
• Examination of the whole scalp under good light, and behind the ears, at the hairline, in the eyebrows and the sides of the nose. Then the nails, the elbows, the knees and the lower back, because psoriasis rarely stays on the scalp alone.
• A look for nits, which is done with a fine comb and a white paper rather than by parting the hair casually.
• Where fungus is suspected: a scraping examined or cultured, because the treatment is weeks of oral medicine and it should not be guessed at.
• Bloods where the itch has no visible cause, or where there are other symptoms: a count, iron studies, thyroid, sugar, liver and kidney function.

What helps

• For seborrhoeic dermatitis: a medicated shampoo used properly, left on the scalp for a few minutes before rinsing, twice weekly at first and then weekly or fortnightly as maintenance. This is a long-term condition that is controlled rather than cured, and the maintenance schedule is the part everyone abandons.
• For psoriasis: a keratolytic to lift the scale before anything else is applied, since a preparation put on top of thick scale does nothing, plus the topical treatment a dermatologist prescribes for the site.
• For ringworm: the full oral antifungal course, finished even after the scalp looks clear, plus treating the sources, the comb, the towel, the pillow and the pet.
• For lice: a proper pediculicide with a repeat dose after the interval the product requires, because the first dose does not kill the eggs, plus wet-combing, plus the household treated together, plus the hats and pillowcases dealt with.
• For contact dermatitis: identify and stop the product, and nothing else until that has been done.
• Keeping the scalp cool, washing sweat out after exertion, and not scratching with nails, which is what turns an itch into an infection.

Where Ayurvedic care sits

• A triphala or neem rinse as a soothing, cleansing wash between medicated treatments, and it is genuinely useful for the itch and the flaking.
• Turmeric and neem preparations, internally in a short defined course and externally as a cooling application for the burning.
• Karanj or nimb oil applied to plaques, which is the topical work where herbal care earns its place.
• Guduchi as the anti-inflammatory support through a longer course.
• Ashwagandha for the sleep, because an itch that breaks sleep is a miserable symptom and the scratch-itch cycle is real.
• What none of these do is kill a dermatophyte inside a hair follicle or remove lice, and recommending them for tinea capitis or pediculosis is how children end up with permanent bald patches.

How we judge it

• Nights of unbroken sleep, and how much scratching is happening.
• Scale thickness and the area of redness, at the hairline and behind the ears, which is where it shows first and clears last.
• Whether the hair is growing back in the affected area, which is the finding that matters most in a child.
• Whether the maintenance wash is still being done, since relapse in this condition is a schedule problem far more often than a treatment failure.