Hair Dye: Is there a risk of exacerbating one's scalp psoriasis?

The psoriasis is a systemic and chronic inflammatory skin eruption. It presents as red and thick plaques that shed. It is characterised by an excessive renewal and accumulation of epidermal cells, leading to a local inflammation. This disease tends to affect adults, with a peak onset generally between 20 and 40 years old. Histological analyses show an increase in the thickness of the epidermis (acanthosis) and incomplete differentiation of keratinocytes (parakeratosis). Its manifestation is triggered by the combination of several risk factors including the immune system, genetic predisposition or environmental factors. The psoriasis can appear on different areas including the scalp. This is the most common location accounting for 50 to 80% of psoriasis cases.

Among the symptoms of scalp psoriasis, we find:

• Appearance of red patches of varying thickness on the scalp. They never extend more than 2 cm from the edge of the scalp;

• Formation of whitish scales and flakes (dandruff) behind the ears, the nape, the forehead and the scalp;

• Feeling of itchiness accompanied by flaking, sometimes with bleeding;

• Cicatricial alopecia for the most severe cases.

Having scalp psoriasis does not mean that one should stop visiting the hairdresser. The condition does not prevent the patient from living a normal life. Moreover, it does not directly contraindicate this either.

Hair dyeing is not prohibited in cases of scalp psoriasis. This skin eruption is partly due to genetic inheritance. However, it is recommended not to dye hair during a flare-up because the scalp is fragile, and to limit its application on the hair while avoiding the epidermis.

The use of chemical hair dyes should be avoided as they may exacerbate this condition. This type of dye sometimes contains toxic agents, such as ammonia, which are responsible for allergies and skin reactions that promote the onset of psoriasis outbreaks. Instead, a person suffering from scalp psoriasis can turn to plant-based dyes that do not contain chemical substances if they wish to colour their hair. These are less likely to cause allergies and reduce the risk of psoriasis flare-ups.

No scientific study has been conducted to observe the effect of hair dye on scalp psoriasis. Generally, we advise you to seek the opinion of your hairdresser beforehand, who will guide you on the best course of action.

To better care for the hair, even if the scalp suffers from psoriasis, certain practices can be adopted. Below are the recommended practices:

• The use of gentle shampoos, whether at home or at the hairdresser's;

• The use of a hairbrush suitable for a scalp suffering from psoriasis;

• For haircare, avoid wearing items that can suffocate the scalp such as hats, beanies or headbands, especially in hot weather;

• When using a hairdryer, ensure to keep it at a distance of 20 cm from the scalp to prevent further sensitising the scalp. It is recommended to allow your hair to air dry.

NICOLAS J. Psoriasis : physiopathologie. Comment l’épithélium peut orienter la réponse immunitaire ou un « ménage à trois » : épithélium, cellule dendritique et lymphocyte T. Bull. Acad. Natle Méd (2014).

SAURAT J. & al. Psoriasis. Dermatologie et infections sexuellement transmissibles (2016).

Le psoriasis du cuir chevelu. Association France Psoriasis (2021).