Woman washing her hair with shampoo.

Can shampoo cause a rash?

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Woman washing her hair with shampoo.

In many people, shampoo is one of the main causes of scalp sensitivity . “Aggressive cleaners or surfactants – present in many shampoos – can wash away the acid mantle of that particular area. That is, they eliminate the natural acidity that protects the skin of the scalp, leaving it vulnerable to dryness and irritation ”, explains CuídatePlus Braulia Mateos Carbonero, a pharmacist in the Dermatology group of the Spanish Society of Family and Community Pharmacy (Sefac) .

“It can happen because the shampoo excessively dries the skin, or irritates it in individuals with sensitive skin, for example in some cases by the use of zinc pyrithione or ichthyol, which are used in dermatitis or scaling conditions,” says José Manuel Carrascosa, member of the Spanish Academy of Dermatology and Venereology (AEDV) .

To start at the beginning, it would be necessary to define a rash , or rash, such as irritation or redness of a specific area of ​​the skin – in this case the scalp -, usually accompanied by itching, burning, burning or tingling and usually remitting In a short space of time.

Other skin factors and pathologies that can cause a rash

“There are many factors that can cause itching or rash on the scalp. The most frequent are: seborrheic dermatitis, pityriasis capitis (known as dandruff ), psoriasis , atopic dermatitis , allergy to dyes or hairdressing products, or even lice infestation , ” Carrascosa enumerates. Mateos adds to the list pathologies such as lichen planus capillary, lupus erythematosus or scleroderma .

The pharmaceutical company details that among the main causes of sensitivity or hypersensitivity of the scalp, the following stand out:

  • Weather conditions: sun, cold, heat or wind.
  • Physical or emotional stress
  • Chemicals present in soaps, cosmetics, water, some drugs and pollution.
  • Hormonal changes: pregnancy , menopause or menstrual cycle .
  • Allergies or food sensitivities .

“When the skin’s natural protective barrier has been altered by one or more of these factors, microinflammations of the scalp develop, which can also become a leading cause of increased sensitivity. This occurs when the skin cells of the scalp become inflamed, increasing vulnerability to irritation, ”says the expert from Sefac.

Does a dry environment worsen the state of a sensitive scalp?

“Logically, a dry environment produces greater dehydration of any area of ​​our skin , and let’s not forget that the scalp is part of it,” says Mateos.

The lack of hydration in the skin can occur in various ways, ranging from typical roughness, scaling and small cracks, to redness, inflammation, constant stiffness and itching. However, these symptoms vary according to the severity and location of dehydration.

Carrascosa points out that worsening of the scalp is more likely in those individuals with a tendency to dry skin, such as atopic dermatitis.

On the contrary, a dry environment favors less washing and, therefore, prevents skin aggressions from hair detergents and keeps the oils produced by our body, important to preserve flexibility and adequate skin hydration.

Can some shampoos trigger peeling and dandruff?

“Most people use hair shampoo on a regular basis and that means that its consumption is massive and essential to satisfy our hygiene. In shampoos we can find some ingredients that would cause conditions on the hair and scalp, but they are not causing dandruff. On the other hand, they can produce some flaking, especially if they are not eliminated well and there are remains in the hair, or have a pH that affects the skin tissue, ”says the expert from Sefac.

Difference between peeling and dandruff

Every two weeks, the skin cells of a healthy scalp renew naturally and are removed during washing and brushing in the form of tiny, invisible scales. However, when the cell renewal process is accelerated, excessive peeling of the scalp occurs , forming groups of dead cells (called dandruff ). These scales are large, white or yellow, and can be very itchy.

Instead, peeling is a natural process of scalp cell renewal . Sometimes, it is too dry and excessive peeling occurs. In this case, the scales are transparent, small and dry. It is also usually accompanied by itching.

Shampoos that dry out the scalp excessively, particularly in individuals with predisposition, may favor flaking or dandruff.

Risks of using unsuitable shampoo

Choosing a shampoo with scientific criteria is a difficult problem for the general population, given the large number of options that are usually found at points of sale, Mateos acknowledges. Shampoos for hair damaged by dyes and permanent hair are stacked on any pharmacy or perfume counter, for dry, oily hair, with dandruff, dull, curly, without volume, sensitive, rough, children … It is a task complicated to choose the right one, but in case of presenting any reaction to any of them it is interesting to specify and avoid successive uses.

It is also necessary to assess not only the pathological criteria, but the cosmetic wishes of the patient. The first thing is to know if the scalp is sick or healthy , since the patient needs a shampoo to treat that pathology. From pediculosis to psoriasis, from impetigo to dandruff, from fungal infection to atopic dermatitis. “In case a product sharpens the symptomatology we must inform the nearest physician, the pharmacist or the dermatologist that corresponds. They will know how to guide us and decide what measures we should take and what products to discard, ”says the expert from Sefac.

Recommendations if you experience a rash on the scalp

Carrascosa and Mateos offer the following recommendations if rash appears on the scalp:

  1. The first action, common sense, would be to look for another shampoo. Try to buy a pharmacy, which does not contain perfumes, with mild cleansers. It may also be because, for example, a therapeutic, anti-dandruff or peeling shampoo is used in an individual with very sensitive skin. This can also favor itching. Undoubtedly, if we associate the itching or rash with a specific product, we should stop using it immediately, and if the problem persists, go to the pharmacist or the nearest dermatologist.
  2. We must know the existence of very effective treatments, such as using a mild shampoo, abundantly lightening the hair and not using a keratolytic shampoo on a regular basis . There are also cosmetic products that can be applied after the hair has been washed to soothe the sensitive scalp.
  3. We must check the amount of shampoo we use , since a large dose in each wash increases the likelihood that the residues irritate the skin of the scalp. In addition, even so-called neutral shampoos may contain some chemicals that cause mild allergic reactions, making the problem worse.
  4. It is important to avoid stressful situations , since this can cause an increase in sensitivity.

Frequently asked questions

Carrascosa acknowledges that GPs or pharmacists are likely to receive more consultations on scalp rash than dermatologists. “In the pharmacy the consultations are varied and a very frequent one is about the proper use of a shampoo, whether there is a rash or if there is none,” says Mateos. To answer questions, the pharmaceutical company provides the answers to the most frequent ones:

  • The important thing is to know that when there is no alteration of the scalp or hair you should simply use a cleansing shampoo, without pharmacological additives of any kind.
  • A shampoo may contain dyes or aromas , but it has no contraindication if you are not allergic.
  • The treatment shampoo should be purchased at the pharmacy , as it ensures the quality of the ingredients.
  • What can be expected from a shampoo is an aid in the treatment of pathologies, but only symptomatically, not curatively .
  • Dandruff can disappear with anti-dandruff shampoos as long as they are used daily while there are symptoms.
  • Fat does not disappear or decrease with shampoos, as it is governed by hormonal impulses. Only a better cleaning and better appearance is achieved.
  • When improvement occurs, treatment should be continued on alternate days , alternating with a mild shampoo without specific attachments.
  • Hygiene shampoos are used by applying a small amount, rinsing and repeating the application. It must be accompanied by a gentle massage.
  • Treatment shampoos require a second one after the first application, in which the product is allowed to act on the scalp for five to seven minutes . This allows you to better achieve your goal.
  • Sensitive scalp is a true pathology that requires an extra-heavy shampoo, with ingredients without risk of sensitization and with the addition of anti-inflammatory substances. The sensitive scalp shampoo should be specific and purchased at the pharmacy.