Sensitive scalp – scratching for a cause and remedy

Sensitive skin presents with unpleasant sensations (stinging, burning, pain, pruritus, and tingling) in response to stimuli that should not provoke such feelings. Any other skin disease does not explain these symptoms. Sensitive skin affects nearly 50% of the population and is more common in women than men. The pathophysiological mechanisms are still being debated, and several hypotheses exist. Sensitive skin can result from a decrease in the skin tolerance threshold, which impairs barrier function and leads to abnormalities in the cutaneous nervous system, making the skin hyperreactive. Sensitive skin is the clinical expression of neurogenic inflammation and can be modulated by many factors. Triggering factors may be endogenous (e.g., stress and emotional or psychopathological disturbances) or exogenous (e.g., ultraviolet light, heat, cold, and wind [Physical factors], or topical products, water, pollutants, and cosmetics [Chemical factors]). A recent meta-analysis showed that the most common triggering factors are cosmetics.

A sensitive scalp is one of the most frequent complaints about sensitive skin. Itching is the main symptom of a sensitive scalp. Some consider it a manifestation of a specific skin disease, whereas others consider it a clinical entity. Sensitive skin can occur in different body areas and a sensitive scalp is a particular condition because of hairs on the head. It is associated with various symptoms as nerves innervate the scalp in a specific pattern.

The first study on this condition showed that 44% of French people, more commonly women suffer from sensitive scalps. Cosmetics probably are the trigger for sensitive scalp. It was found that 36% of 400 subjects in two hospitals declared that they had sensitive scalp skin. Further epidemiological studies revealed that 44% and 32% of subjects suffered from sensitive scalps. Itching affects about 60% of subjects with sensitive scalps. In addition, hair loss was significantly associated with scalp sensitivity.

In a study of 125 Korean adult women, the primary triggering factor cited was hair care products in 65.6% of subjects with sensitive scalps. There are several types of cosmetics care products for hair: Hair conditioners, masks, oils, lotions, and the serums. Because of the presence of surfactants and other potentially irritant substances, shampoos are supposed to be highly involved in developing sensitive scalp.

The clinical manifestations of a sensitive scalp may fall along the four parameters: (a) Subjective scalp skin sensitivity, (b) normal or erythematous scalp skin, (c) association with any alopecia, and (d) associated psychological comorbidity. Subjective scalp skin sensitivity is the fundamental clinical reason why the patient often attends the clinic complaining of stinging, itching, trichodynia, or other abnormal sensations. Trichodynia (“hair pain”) is a painful sensation on the scalp. Affected patients appreciate it when they comb and part their hair, which sometimes occurs spontaneously. The pain symptom is more intense in women and with cases of scarring alopecia. As for the origin of trichodynia, many authors think that symptoms are due to psychological factors such as depression and anxiety, sleep disorders, and stress. A person’s skin with a sensitive scalp may appear normal or show more or less intense erythema (red scalp). When examined using a dermatoscope, a sensitive scalp demonstrate dilated capillaries and telangiectasias, with no other specific findings. The sensitive scalp may occur alongside some alopecia, more frequently telogen effluvium or androgenetic alopecia, significantly so if associated with trichodynia. Psychological comorbidity is common in sensitive scalps, mainly when it is associated with trichodynia.

The sensitive scalp is mainly a subjective syndrome and the diagnosis is commonly made by interviewing subjects and asking them whether they have sensitive skin. Clinical history should focus on haircare habits, cosmetics, treatments, and factors considered triggers by the patient. The diagnosis is based on the result of the physical examination (normal or erythema) and trichoscopy. Objective tests with lactic acid or capsaicin are problematic in the presence of hairs. Rule out secondary sensitive scalp disorders, which always involve skin lesions on the scalp and possibly other areas. Dry scalp symptoms are often observed in patients with atopic dermatitis, seborrheic dermatitis, or pityriasis capitis. Remember SCALLP acronym to recall the most common causes of scalp itch quickly. It stands for Seborrheic dermatitis, Contact dermatitis, Anxiety, Lichen planopilaris, Lice, and Psoriasis. One should also consider the possibility of the red scalp syndrome. The red scalp syndrome is characterized by of itching, stinging, and burning scalp having erythema with papules, pustules, and telangiectasias. The disorder is probably a variant of rosacea localized to the scalp. Similar to rosacea is characteristically resistant to treatment with topical steroids and responds to oral tetracyclines. The red scalp syndrome may be associated with androgenetic alopecia.

The initial approach to sensitive scalp should attempt to eliminate or diminish the triggers, mainly hair products and topical treatments (such as minoxidil), including mechanical devices and exfoliants. Replace them with bland cleansing products containing hydrating elements such as glycerin, hyaluronic acid, and relipidizing agents such as vegetable oil or ceramides. Barrier strengthening improves the scalp condition directly or indirectly and thus alleviates sensitivity to external stimuli. Patients receiving topical minoxidil for alopecia can switch to oral minoxidil if there are no contraindications. Patients on topical steroids with side effects may be put on a short course of systemic corticosteroids for 2 weeks, followed by topical use of pimecrolimus or tacrolimus. The horny layer integrity on the scalp skin can be restored with moisturizing creams containing hyaluronic acid before applying pimecrolimus. If the subjective symptoms — stinging, trichodynia, and pruritus — are intense, oral gabapentin can be added, starting at 300 mg/day, or pregabalin, at 75 mg every 12 h. The dose and frequency can be increased if necessary. Mesotherapy with growth factor-rich plasma has several uses and few associated risks.