Hair dye safety

What it is

Permanent dark dyes usually contain PPD.

How it works

PPD is a potent allergen that can cause severe reactions in sensitised people.

Why it matters on darker skin

Allergic swelling may look dark rather than red.

Causes and triggers

Previous black henna tattoos increase risk.

What helps — and why it works

Patch test 48 h before each use: detect allergy. Expected timeline: 48 h. Choose PPD-free options if sensitive: avoid allergen.

More detail

Permanent dark dyes work by allowing small colourless molecules, usually para-phenylenediamine (PPD) or toluene-2,5-diamine, to enter the hair and react with an oxidiser to form large coloured molecules. Before the reaction completes, PPD is a strong sensitiser. People can use dye for years and then develop an allergy, so a patch test 48 hours before each use is worthwhile. Reactions range from itchy scalp and ears to severe swelling of the face and eyelids, which needs urgent medical care. 'Black henna' temporary tattoos often contain high levels of PPD and are a common way people become sensitised; pure henna is reddish-brown, never black. If you have reacted before, do not use the same dye again; some PPD-free dyes contain related chemicals that can also cause reactions, so discuss safer options with a dermatologist, who can arrange formal patch testing.

What to avoid and why

Avoid black henna tattoos.

Common mistakes

• Skipping patch tests because you've dyed before.

Handling textured hair gently

Coily and curly hair is naturally the most fragile hair type because each bend in the strand is a weak point and natural oils travel down it slowly. That makes handling — how often and how firmly hair is combed, styled and pulled — as important as which products you buy. Detangle only when hair is wet and coated in conditioner, working in sections from the ends towards the roots with fingers or a wide-tooth comb. Keep heat to the lowest effective setting and always use a heat protectant. Sleep on satin or silk, or wear a satin bonnet, to reduce friction. Between wash days, a water-based leave-in followed by a light oil or cream helps hold moisture. Give the scalp attention too: it is skin, and needs regular cleansing, especially under wigs, weaves and braids, to prevent build-up, itch and infection. Any style that hurts, causes bumps or leaves the scalp tender is too tight and should be loosened. Hair grows about one centimetre a month, so changes in care take two to three months to show in length and thickness.

Scalp health and product choice

Choose a shampoo that suits the scalp and a conditioner that suits the lengths: the scalp may need cleansing or a medicated shampoo while the ends need moisture. Fragrance, essential oils and heavy waxes can irritate a sensitive scalp or cause build-up, and heavy oils on the scalp may worsen dandruff. Look for a clear ingredient list and a NAFDAC number, and patch-test new dyes and relaxers 48 hours before every use. Products that promise dramatic growth are usually untested; the treatments with the best evidence for pattern hair loss are medicines such as minoxidil, which should be started only after speaking to a pharmacist or doctor. Signs that you need medical advice rather than a new product include patches of hair loss, scarring or shiny skin, pain, pus, or shedding that continues for more than six months.

Questions to ask your doctor or pharmacist

Useful questions include: What do you think is causing this? Is it likely to come back, and how can I prevent it? Which products should I stop? How long before I should expect improvement, and when should I come back if it isn't better? Are there side effects to watch for? Is this treatment safe if I am pregnant, breastfeeding or for my child? Writing your questions down, bringing your products (or photos of their labels) and taking dated photos of the problem make an appointment much more useful.