Seborrhoeic dermatitis is a common chronic skin condition that mainly affects the skin areas most rich in sebaceous glands, such as the scalp, face, ears and upper chest. Characterised by redness, oily scaling and itching, this condition can affect adults and children, with a significant impact on quality of life, although it is not contagious or dangerous.
Causes
The itching, irritation and flaking that characterise seborrhoeic dermatitis are caused by excessive sebum production. This overproduction of sebum can encourage the growth of microorganisms responsible for skin inflammation, such as Malassezia, a yeast that normally resides on the skin but multiplies in the presence of excess sebum, triggering an inflammatory response. Several factors have been identified that may contribute to increased sebum production:
- Alterations in the skin microbiome: an imbalance in the skin flora can encourage the proliferation of pathogenic microorganisms at the expense of beneficial ones, contributing to skin inflammation.
- Stress: stress can stimulate the production of hormones such as cortisol which, once released into the bloodstream, affects various tissues, including the skin. This occurs because cortisol increases the production of adrenal androgens, which directly affect the sebaceous glands, increasing sebaceous production.
- Hormonal imbalances: hormones regulate the activity of the sebaceous glands and hormonal changes can worsen seborrheic dermatitis. Consequently, this condition is more common at stages such as puberty, pregnancy, menopause or during seasonal changes.
- Diet: Foods with a high glycaemic index, such as refined sugars, carbohydrates, dairy products, fried foods or foods high in saturated fats, can lead to increased sebum production.
- Genetic predisposition and associated diseases: conditions such as Parkinson’s disease or HIV are more frequently associated with this skin disorder. Parkinson’s disease causes changes in the autonomic nervous system, which controls the activity of the sebaceous glands, and a reduction in dopamine levels due to degeneration of dopaminergic neurons. Dopamine is involved in regulating the sebaceous glands by inhibiting their activity. Its deficiency, as occurs in Parkinson’s disease, can lead to overactivity of the glands, resulting in increased sebum production and predisposition to seborrhoeic dermatitis. There is also a dysfunction of the sebaceous glands in HIV, which can predispose to yeast infection.
In addition, environmental factors such as cold and dry weather can produce skin stress and aggravate seborrhoeic dermatitis, as low temperatures and low humidity contribute to increased skin dryness and alter the skin’s protective barrier. During the winter months, for example, prolonged exposure to cold wind and temperature changes between heated indoor and outdoor environments can worsen the symptoms.
Symptoms
The skin manifestations of seborrhoeic dermatitis can be more or less obvious and appear all over the body, including the face. Let’s see what the main ones are.
- Dandruff and greasy scales and yellowish plaques on the scalp, eyebrows, nose, ears and upper chest.
- Skin reddening resulting from an inflammatory process triggered by various internal and external triggers. At the eyebrows and eyelids it may be accompanied by blepharitis (inflammation of the eyelids), but can also appear at skin folds, such as at the armpits and groin.
- Variable itching, sometimes accompanied by a burning sensation of the skin. Itching is a symptom that should not be underestimated because, when intense, it can lead to the development of infections following scratching.
- Thick scabs, especially in severe cases.
- Hair loss, which can occur when intense itching due to seborrhoeic dermatitis leads to repeated scratching. The mechanical action of scratching can weaken the hair, making it more prone to breakage and promoting thinning in certain areas of the scalp. In addition, excoriations and irritations may appear on the skin, further aggravating the situation.
In infants, this condition is known as milky scab and presents as thick, yellowish, sometimes brown crusts on the scalp. Infant crusts can be either dry or greasy and are often confined to the top of the head, but can also extend to the forehead and eyebrows. It is a benign and temporary condition that tends to resolve spontaneously within the first year of life. If it persists or is particularly extensive, it is always advisable to consult the paediatrician or a dermatologist.
Diagnosis
Seborrhoeic dermatitis is a skin disease that requires a careful dermatological examination for an accurate diagnosis, as its symptoms can easily be confused with other skin diseases. Among them, scalp psoriasis, atopic dermatitis, rosacea and even acne show similar signs, such as skin lesions, redness and skin patches. However, each of these conditions has distinctive features that dermatological patients cannot recognise on their own.
During the dermatological examination, the specialist examines the affected areas, assesses the appearance of the skin lesions and collects the patient’s medical history. In some cases, specific diagnostic tests may be necessary to exclude other conditions, such as atopic eczema.
Once the diagnosis has been confirmed, the dermatologist will provide personalised advice and prescribe an appropriate treatment. This may include the use of a specific dermatological cream with antifungal, soothing or keratolytic properties to reduce inflammation and scales. The therapeutic approach may vary depending on the severity of the pathology and the patient‘s needs.
Dermatological treatment aims not only to control symptoms but also to prevent recurrences, thus ensuring optimal management of this chronic dermatological disorder for the patient.
Remedies and treatments
As we have seen, the management of seborrhoeic dermatitis requires a constant and customised approach, including the use of cosmetic products to reduce skin inflammation, itching and flaking. Here are the main ones:
- Specific shampoos to be used at least twice a week, containing active ingredients such as:
- Cyclopirox, which helps normalise the surface microbial flora, alleviating the most annoying epidermal sensations.
- Salicylic acid. In seborrhoeic dermatitis, the use of keratolytics such as salicylic acid helps remove scales and free sebaceous follicles, improving the skin’s appearance and reducing sebum accumulation.
- D-Panthenol, which leaves hair soft and moisturised.
- Soothing creams to be applied to the face and other affected skin areas, based on:
- Lithium gluconate, which regulates the skin’s microflora and relieves irritation.
- Zinc gluconate and nicotinamide, which have a soothing and sebum-normalising action and reduce the oily appearance of the skin.
When these products fail to adequately control skin inflammation, the doctor might indicate antifungals such as ketoconazole, also available in shampoo form, which inhibits the growth of the Malassezia fungus by interfering with the synthesis of its cell membrane. In more severe cases, he may prescribe topical corticosteroids, which must be used for short periods to avoid side effects. Moreover, these topical drugs do not act on the cause (the proliferation of skin fungus), but only on the symptoms.
Tips for managing seborrhoeic dermatitis
Adopting some good daily habits is essential to control symptoms and ensure skin well-being. Here are some useful tips.
- Dermatological advice
- Take care of skin hygiene, keeping it clean and moisturised using gentle, specific products.
- Avoid washing too often and with very hot water, which can irritate the skin.
- Limit the use of harsh detergents, which compromise the skin barrier.
- Protect the skin from extreme weather conditions, such as intense cold, and do not expose it to the sun without a protective cream.
- Stress management
- Reduce physical and emotional stress with relaxation techniques and time for rest.
- Carry out regular physical activity.
- Healthy lifestyle
- Avoid aggravating factors such as smoking, alcohol consumption and obesity, which can promote skin inflammation and sebum production.
- Follow a balanced diet, including foods containing omega-3 fatty acids, such as salmon, mackerel, sardines, walnuts and olive oil, which have anti-inflammatory properties. Foods rich in antioxidants and vitamins, such as fresh fruit and green leafy vegetables, can also help. Vitamins such as C (citrus fruits, kiwi), E (almonds, avocado) and beta-carotene (carrots, pumpkin) contribute to skin regeneration. On the other hand, it is preferable to limit the consumption of foods rich in saturated and trans fats, such as fried foods, industrial snacks and ultra-processed products, which can worsen skin inflammation.
- Anti-mite routines. The mite is a tiny arachnid that lives in our home environments, feeding on the residues of skin and hair it finds on mattresses and pillows. Although these little animals are almost invisible to the naked eye, their faeces contain enzymes that can irritate the skin, accelerating the process of flaking. This is why it is important to keep your living environment clean by removing dust, especially from pillows, sofas and mattresses.
Seborrhoeic dermatitis is a chronic but manageable condition. A combined approach integrating skin care, specific treatments and management of risk factors can significantly improve quality of life. It is always advisable to consult a dermatologist for an accurate diagnosis and customised treatment.
Sources:
https://my.clevelandclinic.org/health/diseases/14403-seborrheic-dermatitis
https://www.aad.org/public/diseases/a-z/seborrheic-dermatitis-overview
