Nails and hair: what diseases affect them?

ongles et cheveux

Marie is worried, she is losing a lot of hair at the moment. It feels fragile and it’s breaking all the time. What surprises her is that at the same time, her nails are all soft and a little yellowed.

She wonders about the link between her hair and her nails…

Olà, It’s me, Dr. Joy !

It may sound strange to you, but nails and hair are in the same family as body hair. We call them skin appendages. And they too can be affected by diseases.

I’ll explain it all to you, vamos?

Composition of nails and hair

A skin appendage is a protective organ characterised by intense keratinisation. Keratin is a fibrous protein and the main component of the skin’s surface layer, the epidermis.

It is hard, resistant and protective.

The nail is a horny plate about 0.5 millimetres thick. It is made of keratin and its main role is to protect the tips of the fingers and toes. It consists of a body and a root that allows it to grow. It grows by about 0.14 to 0.40 millimetres per day.

It takes about 6 months for a fingernail to grow back completely. Toenails grow twice as slowly.

Hair also consists of 95% keratin, our fibrous protein. As it is insoluble in water, it ensures a real role of impermeability and protection for the hair.

There are about 18 amino acids in the composition of hair. These include, for example, proline, threonine, leucine and arginine. Keratin is particularly rich in cysteine (a type of sulphur amino acid). It is cysteine that gives hair its rigidity and strength.

For the record, a single strand of hair can support up to 100g without breaking.

But this is not the primary objective. Its main role is to protect the head and scalp.

Nails and hair diseases

Like all other parts of the human body, nails and hair can be affected by diseases. With age, all the skin appendages thicken.

This can lead to:

  • Alopecia: a loss of hair on the body. Hair loss is often the main cause for concern for aesthetic and psychological reasons. But it can also be a symptom of a systemic disease. It is therefore not to be taken lightly.
  • Ringworm: an infection of the hair or body hair due to a fungus that develops on the scalp. It manifests as small pimples and dandruff, sometimes with erythematous lesions. The hair may be brittle, and the scalp may experience localised hair loss. Ringworm is transmitted by direct contact or exchange of contaminated objects (hairbrush).
  • Seborrheic dermatitis: this is a chronic inflammatory skin condition. It is manifested by red patches and small pieces of skin that peel off the scalp, creating dandruff. It mainly affects men and develops in flare-ups.
  • Peladia: this is an autoimmune dermatological disease, i.e. a disease where the immune system turns against one’s own body. It can affect the nails or hair. When it affects the hair, it leads to alopecia in patches.
  • Onychomycosis: these are fungi (mycosis) that affect the nails. They degrade the keratin. It is characterised by a yellowish or brownish discolouration of the nail, thickening, a change in shape, brittle nails, and pain when the nail is pressed. This condition tends to affect older people.
  • Onychogryphosis: this is a condition characterised by significant growth of the nails, they thicken, harden, lengthen and curve. It mainly affects older people.
  • Ingrown toenail: this is related to a growth of the nail edges into the adjacent skin. It mainly affects toenails. They quickly become painful, red and can be warm to the touch. If not treated in time, it can become infectious.

More seriously, there are also carcinomas and melanoma of the nail (cancer).

Excessive hair loss or weakened nails can also be a symptom of another disease, or the consequence of certain drug treatments (chemo for example).

If in doubt, I recommend that you consult a dermatologist or a general practionner who will be able to advise you.

Taking care of your hair and nails

To avoid damage to your hair and nails, you must take care of them. Here are some tips to help you do so.

  • Maintain and nourish your hair/nails regularly
    To care for your nails:
  1. Use a moisturiser to hydrate hands and nails throughout the day
  2. Use gloves when doing housework, especially when cleaning or using water and detergents
  3. Avoid using hand sanitisers unless absolutely necessary
  4. Avoid rough manicures/pedicures and cuticle removal.

Concerning your hair:

  1. Wash hair according to its needs.
    There is no problem with washing it daily, as long as you use a shampoo that is suitable for your hair
  2. Use a hair mask or conditioner if the hair is dry (avoid if the scalp is oily)
  3. Avoid high temperatures when drying hair and avoid cosmetic hair treatments with high temperatures (e.g. straighteners)
  4. It is better to blow dry hair than to let it air dry. There is a risk that the scalp and hair roots will not dry completely until several hours after washing, which promotes oily hair and scalp dermatitis.
  • Eat a good diet

A healthy, balanced diet is recommended to maintain good health. Focus on foods rich in protein, B vitamins and minerals such as zinc, iron, calcium and magnesium. These minerals can be found in fruit, vegetables, nuts and also in meat.

Avoid processed products such as biscuits, ready meals, etc. Get back into the kitchen and your hair and nails will thank you. Also, remember to moisturise well throughout the day.

  • Strengthen your nails and hair naturally

Give your nails and hair a boost. In addition to getting the right things in your diet, you can use plant oils to improve the quality of your hair and nails.

Those that have proven their effectiveness are: castor oil, black cumin oil, sweet almond oil and argan oil.

You can combine all this with food supplements rich in vitamin B, biotin and cysteine for example, which have an even more remarkable effect..

I also recommend that you do not share your skincare items (brushes, combs, towels, etc.) or your hats, caps, etc.

This brings us to the end of this article.

Now that hair and nails are no longer a mystery to you, it’s up to you to take care of them properly.

We’ll see each other soon for more learning.

Beijinhos, Dr Joy!


This information is not a substitute for medical advice. 

You must seek the advice of your doctor or another qualified health professional with any questions you may have regarding your health condition.

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