The search for a youthful appearance often starts with simple cosmetic treatments like altering the hair color and hiding the grey with hair dyes. The popularity of hair dye is not isolated to those looking at masking the signs of aging and changing fashion trends very often involves changing the hair color. However hair dye allergies affect many who use dyes and can cause a host of symptoms ranging from skin rashes and ’scalp pimples’ to thinning and hair loss. Unfortunately the popularity of hair dye is unlikely to wane as coloring or tinting the hair is still a common practice.

What is a hair dye allergy?

Initially, the allergy to a hair dye presents as skin sensitivity, with itching and burning in response to the application of a hair dye. A hair dye allergy is classified as an allergic contact dermatitis where a delayed hypersensitivity reaction occurs in response to the chemical constituents of the hair dye. While itching and burning may be noticed, at times there are no symptoms upon applying the dye and any signs of an allergy appears weeks after the hair dye application. Continued exposure to the hair dye can aggravate the allergy further.

Symptoms of a Hair Dye Allergy

• Inflammation of the affected area (mostly the head area).
• The skin has a red appearance with a presence of a rash.
• Itchy and burning sensations often accompany the allergy.
• Temporary thickening of the skin can occur.
• The skin may become dry and scaly.
• Eruption of blisters or ’scalp pimples’.
• In some cases severe swelling can occur.
• Systemic allergic reactions may occur in hypersensitive individuals.
• Secondary infection of the scalp rash or blisters will result in thick crusts, and oozing pus from the scalp.

Causes of a Hair Dye Allergy

The cause of most hair dye allergies is linked to a substance called paraphenyenediamine (PPD) which is commonly found in permanent hair dyes. PPD is banned in some European countries due to its tendency to cause hair dye allergies and severe skin irritation. Commercial hair dyes that are widely used in the retail market contain PPD along with hydrogen peroxide. PPD functions as a replacement for the color of the hair whilst hydrogen peroxide breaks down the melanin (natural pigment) of the hair. A reaction occurs with PPD and hydrogen peroxide which may result in a partial oxidation of the dye color. During this stage an allergic reaction can occur if the PPD is not completely oxidized.

Preventing a Hair Dye Allergy

• It is advisable to do an allergy sensitive test or a patch test to determine if the skin will react to the hair dye preparation.
• Apply hair dye on a small sensitive area of the skin for 5 to 10 minutes.
• Wash off the area completely with warm to cold water.
• After a waiting period of 48 to 72 hours, if a rash appears, this indicates an allergy to the hair dye. Do not use the dye if a reaction is evident.
• If no reaction occurs, the skin is unlikely to react to the hair dye preparation.
• Stop using the hair dye or reduce the frequency of application.
• Switch to a ‘non-permanent’ or a natural hair dye preparation like henna.
• Wait for the symptoms to disappear or resolve before considering another hair dye application.

Treatment of Hair Dye Allergies

• In cases where the allergy is present the use of a corticosteroid cream can be effective to reduce the itching, burning and skin rash.
• Anti-histamines may offer some short term relief for the itching.
• In acute reactions, immediately after applying the hair dye, a thorough rinsing with cold water may reduce the severity of the itching or burning. However this is unlikely to prevent the development of a rash.
• Secondary bacterial or fungal infections should be treated immediately to prevent further complications like hair loss.