Seborrhoeic dermatitis (also spelled seborrheic dermatitis in American English) is a long-term skin disorder. Symptoms include flaky, scaly, greasy, and occasionally itchy and inflamed skin. Areas of the skin rich in oil-producing

gland A gland is a Cell (biology), cell or an Organ (biology), organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also funct ...

s are often affected including the

scalp The scalp is the area of the head where head hair grows. It is made up of skin, layers of connective and fibrous tissues, and the membrane of the skull. Anatomically, the scalp is part of the epicranium, a collection of structures covering th ...

, face, and chest. It can result in social or self-esteem problems. In babies, when the scalp is primarily involved, it is called

cradle cap Cradle cap is crusty or oily scaly patches on a baby's scalp. The condition is not painful or itchy, but it can cause thick white or yellow scales that are not easy to remove. Cradle cap most commonly begins sometime in the first three months b ...

. Mild seborrhoeic dermatitis of the scalp may be described in lay terms as

dandruff Dandruff is a skin condition of the scalp. Symptoms include flaking and sometimes mild itchiness. It can result in social or self-esteem problems. A more severe form of the condition, which includes inflammation of the skin, is known as s ...

due to the dry, flaky character of the skin. However, as dandruff may refer to any dryness or scaling of the scalp, not all dandruff is seborrhoeic dermatitis. Seborrhoeic dermatitis is sometimes inaccurately referred to as seborrhoea. The cause is unclear but believed to involve a number of genetic and environmental factors. Risk factors for seborrhoeic dermatitis include poor immune function,

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...

, and alcoholic pancreatitis. The condition may worsen with stress or during the winter. '' Malassezia'' yeast is believed to play a role. It is not a result of poor

hygiene Hygiene is a set of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refer ...

. Diagnosis is typically clinical and based on the symptoms present. The condition is not contagious. The typical treatment is topical antifungal cream and anti-inflammatory agents. Specifically,

ketoconazole Ketoconazole, sold under the brand name Nizoral, among others, is an antiandrogen, antifungal drug, antifungal, and antiglucocorticoid medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin inf ...

or ciclopirox are effective. Seborrhoeic dermatitis of the scalp is often treated with shampoo preparations of

, zinc pyrithione, and

selenium Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...

, although the latter has been partly discontinued due to concerns of selenium in higher concentrations being

carcinogenic A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and Biological agent, biologic agent ...

. The condition is common in infants within the first three months of age or adults aged 30 to 70 years. It tends to affect more males. Seborrhoeic dermatitis is more common in African Americans, among immune-compromised individuals, such as those with HIV, and individuals with

Signs and symptoms

Seborrhoeic dermatitis typically appears as dry, white, flaky skin. The flakes can be fine, loose, and diffuse or thick and adherent. Additionally, flakes can appear yellow and oily or greasy. In addition to flaky skin, seborrhoeic dermatitis can have areas of red, inflamed, and itchy skin that coincide with the area of skin flaking, but not all individuals have this symptom. Seborrhoeic dermatitis of the scalp can appear similarly to dandruff. When the scalp is affected, there can be associated temporary hair loss. Such hair loss varies in appearance from diffuse thinning to patchy areas of hair loss. On close inspection, the locations where hair has thinned may have broken stubs of hair and pustules around the hair follicles. Individuals with more pigmented skin tones may experience increased or decreased skin pigmentation in affected areas. Various locations can be affected by seborrhoeic dermatitis. Commonly affected areas include the face, ears, scalp, and across the body. It is less common in intertriginous areas, which are areas where the skin folds and comes into contact with itself, such as the groin or the underarms. Seborrhoeic dermatitis' symptoms are typically mild and appear gradually but are often persistent, lasting weeks to years. Individuals with seborrhoeic dermatitis are subject to recurrent bouts and it may be a lifelong condition. Seborrhoeic dermatitis can also occur quickly and severely in patients with

Human Immunodeficiency Virus The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause AIDS, acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of th ...

(HIV). This is sometimes the first indication of HIV.

Causes

The cause of seborrhoeic dermatitis has not been fully clarified. In addition to the presence of ''Malassezia'', genetic, environmental, hormonal, and immune-system factors are necessary for and/or modulate the expression of seborrhoeic dermatitis. The condition may be aggravated by illness, psychological stress, fatigue, sleep deprivation, change of season, and reduced general health.

Fungi

The condition is thought to be due to a local

inflammatory response Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

to overgrowth by '' Malassezia''

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

species in

sebum A sebaceous gland or oil gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur ...

-producing

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

areas including the

face The face is the front of the head that features the eyes, nose and mouth, and through which animals express many of their emotions. The face is crucial for human identity, and damage such as scarring or developmental deformities may affect th ...

chest The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...

back The human back, also called the dorsum (: dorsa), is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck. It is the surface of the body opposite from the chest and the abdomen. The vertebral c ...

underarm The axilla (: axillae or axillas; also known as the armpit, underarm or oxter) is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm and ...

s, and

groin In human anatomy, the groin, also known as the inguinal region or iliac region, is the junctional area between the torso and the thigh. The groin is at the front of the body on either side of the pubic tubercle, where the lower part of the abdom ...

. This is based on observations of high counts of ''Malassezia'' species in skin affected by seborrhoeic dermatitis and on the effectiveness of

antifungal An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as ...

s in treating the condition. Species of ''Malassezia'' implicated in Seborrhoeic dermatitis include '' M. furfur'' (formerly '' Pityrosporum ovale''), '' M. globosa'', '' M. restricta'', '' M. sympodialis'', and '' M. slooffiae''. ''Malassezia'' appears to be a significant factor in seborrhoeic dermatitis, but it is thought that other factors are necessary for the presence of ''Malassezia'' to result in seborrhoeic dermatitis. For example, summer growth of ''Malassezia'' in the skin alone does not result in seborrhoeic dermatitis. Besides antifungals, the effectiveness of anti-inflammatory drugs, which reduce inflammation, and

antiandrogen Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs that prevent androgens like testosterone and dihydrotestosterone (DHT) from mediating their biological effects in the body. They act by blocking t ...

s, which reduce

production, provide further insights into the

pathophysiology Pathophysiology (or physiopathology) is a branch of study, at the intersection of pathology and physiology, concerning disordered physiological processes that cause, result from, or are otherwise associated with a disease or injury. Pathology is ...

of seborrhoeic dermatitis.

Bacteria

Several bacteria, including ''Propionibacterium'' species and ''Staphylococcus aureus'', have been shown to have some level of interaction with seborrhoeic dermatitis, though their exact impact is not known.

Nutrition

Seborrhoeic dermatitis-like eruptions are also associated with pyridoxine ( vitamin B₆) and riboflavin ( vitamin B₂) deficiency. In children and babies, issues with Δ⁶-desaturase

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

s have been correlated with increased risk.

Immune dysfunction

Those with

immunodeficiency Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that aff ...

(especially

infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

with HIV) and with

neurological disorder Neurological disorders represent a complex array of medical conditions that fundamentally disrupt the functioning of the nervous system. These disorders affect the brain, spinal cord, and nerve networks, presenting unique diagnosis, treatment, and ...

s that may impact immune system function such as

(for which the condition is an autonomic sign) and

stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...

are particularly prone to it.

Climate

Climate can affect seborrheic dermatitis, but there is a lack of consensus about which climates tend to exacerbate seborrheic dermatitis the most. Some studies show low

humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...

and low

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

are responsible for the high frequency of seborrheic dermatitis. Others suggest hot environments may also worsen seborrhoeic dermatitis. Yet another described that high humidity and low UV exposure are culpable. Dry skin and an impaired skin barrier contribute to the condition. It is likely that climate and weather variations affect the water and lipid content of skin.

Mechanism

Seborrhoeic dermatitis is a complex condition with many interacting factors that are not yet fully explained. In general, the major factors that influence the development and severity include ''Malassezia'' yeast present on and in the skin, skin production of oily sebum, and a subsequent inflammatory response against ''Malassezia'' and their byproducts. Additional factors involved in the condition are a compromised skin barrier, the makeup and amount of sebum produced, the character of the immune response and inflammation, and the presence of other microbe species inhabiting the skin. A suggested series of events leading to seborrhoeic dermatitis is an initially damaged skin barrier and abnormal sebum production, which leads to a change in the microbiome of the skin that in turn elicits an immune response. An alternative explanation is an increase in sebum production feeding an increase in the ''Malassezia'' population that instigates inflammation; the inflammation then causes cellular changes that damage the skin barrier. This barrier disruption then encourages additional ''Malassezia'' growth and inflammation and again worsens skin barrier function.

Diagnosis

Typically, seborrhoeic dermatitis is a clinical diagnosis based on a physician's expertise in identifying and differentiating skin conditions based on the history of the individual and the appearance of the skin. However, seborrhoeic dermatitis may also be diagnosed with additional testing. The least invasive test is a visual inspection in the clinic using a Wood's Lamp. A KOH test can also be used, where skin scraping of the affected skin may also be taken and prepared with

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

(KOH) and visualized under a microscope to look for ''Malassezia'' or other microbiological cells. Additionally, a fungal culture of the affected skin may be taken to attempt to grow and identify the causative organism.

Differential diagnosis

Seborrhoeic dermatitis can look similar to other skin conditions that share its characteristic dry, flaky, scaly, and inflamed appearance, but have different causes and treatments. Physicians use the history of the individual with the skin condition as well as other tests to identify which disorder is present. Other conditions that may be confused with seborrhoeic dermatitis based on appearance are listed below. *

Atopic dermatitis Atopic dermatitis (AD), also known as atopic eczema, is a long-term type of inflammation of the skin. Atopic dermatitis is also often called simply eczema but the same term is also used to refer to dermatitis, the larger group of skin conditi ...

(eczema) *

Contact dermatitis Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes ...

Psoriasis Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by patches of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small localized patches to complete b ...

Tinea capitis Tinea capitis (also known as "herpes tonsurans", "ringworm of the hair", "ringworm of the scalp", "scalp ringworm", and "tinea tonsurans") is a cutaneous fungal infection ( dermatophytosis) of the scalp. The disease is primarily caused by dermato ...

and

tinea corporis Tinea corporis is a fungal infection of the body, similar to other forms of tinea. Specifically, it is a type of dermatophytosis (or ringworm) that appears on the arms and legs, especially on glabrous skin; however, it may occur on any superfici ...

Candidiasis Candidiasis is a fungal infection due to any species of the genus '' Candida'' (a yeast). When it affects the mouth, in some countries it is commonly called thrush. Signs and symptoms include white patches on the tongue or other areas of the ...

Tinea versicolor Tinea versicolor (also pityriasis versicolor) is a condition characterized by a skin eruption on the trunk and proximal extremities. The majority of tinea versicolor is caused by the fungus '' Malassezia globosa'', although '' Malassezia furfur' ...

Pityriasis rosea Pityriasis rosea is a type of skin rash. Classically, it begins with a single red and slightly scaly area known as a "herald patch". This is then followed, days to weeks later, by an eruption of many smaller scaly spots; pinkish with a red edge ...

Impetigo Impetigo is a contagious bacterial infection that involves the superficial skin. The most common presentation is yellowish crusts on the face, arms, or legs. Less commonly there may be large blisters which affect the groin or armpits. The les ...

* Drug reaction * Cutaneous T-Cell Lymphoma

Management

Medications

A variety of different types of medications can reduce symptoms of seborrhoeic dermatitis. These include certain

s, anti-inflammatory agents like

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are invo ...

s and

nonsteroidal anti-inflammatory drug Non-steroidal anti-inflammatory drugs (NSAID) are members of a Indication (medicine), therapeutic drug class which Analgesic, reduces pain, Anti-inflammatory, decreases inflammation, Antipyretic, decreases fever, and Antithrombotic, prevents bl ...

s, and

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provides ...

s, among others. Treatments must take into consideration potential side effects, especially with long-term use given the chronic nature of seborrhoeic dermatitis. Initial therapy is usually a topical preparation with an agreeable side effect profile.

Antifungals

Regular use of an

over-the-counter Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid pres ...

or prescription

shampoo Shampoo () is a hair care product, typically in the form of a viscous liquid, that is formulated to be used for cleaning (scalp) hair. Less commonly, it is available in solid bar format. (" Dry shampoo" is a separate product.) Shampoo is use ...

cream Cream is a dairy product composed of the higher-fat layer skimmed from the top of milk before homogenization. In un-homogenized milk, the fat, which is less dense, eventually rises to the top. In the industrial production of cream, this proces ...

is a common treatment. The topical antifungal medications

and ciclopirox have the best evidence. Ketoconazole should be used twice per week. Shampoo or soap containing zinc pyrithione or selenium disulfide is also used. These options should be used daily but may also be used in conjunction with a ketoconazole shampoo regimen on alternate days. It is unclear if other antifungals are equally effective, as this has not been sufficiently studied. Antifungals that have been studied and found to be effective in the treatment of seborrhoeic dermatitis include

fluconazole Fluconazole is an antifungal medication used for a number of fungal infections. These include candidiasis, blastomycosis, coccidioidomycosis, cryptococcosis, histoplasmosis, dermatophytosis, and tinea versicolor. It is also used to pr ...

miconazole Miconazole, sold under the brand name Monistat among others, is an antifungal medication used to treat ring worm, pityriasis versicolor, and yeast infections of the skin or vagina. It is used for ring worm of the body, groin (jock itch), a ...

, bifonazole, sertaconazole,

clotrimazole Clotrimazole, sold under the brand name Lotrimin, among others, is an antifungal medication. It is used to treat vaginal yeast infections, oral thrush, diaper rash, tinea versicolor, and types of ringworm including athlete's foot and jock itc ...

, flutrimazole, ciclopirox,

terbinafine Terbinafine, sold under the brand name Lamisil among others, is an antifungal medication used to treat pityriasis versicolor, onychomycosis, fungal nail infections, and ringworm including jock itch and athlete's foot. It is either oral adminis ...

, butenafine, selenium disulfide, and lithium salts such as lithium gluconate and lithium succinate. Topical climbazole appears to have little effectiveness in the treatment of seborrhoeic dermatitis. Systemic therapy with oral antifungals including

itraconazole Itraconazole, sometimes abbreviated ITZ, is an antifungal medication used to treat a number of fungal infections. This includes aspergillosis, blastomycosis, coccidioidomycosis, histoplasmosis, and paracoccidioidomycosis. It may be given ...

is effective, but adverse side effects have been documented for

and

, with the latter not recommended for use, while

, with its good safety profile, is the most commonly prescribed.

Terbinafine Terbinafine, sold under the brand name Lamisil among others, is an antifungal medication used to treat pityriasis versicolor, onychomycosis, fungal nail infections, and ringworm including jock itch and athlete's foot. It is either oral adminis ...

is said to be effective, but with adverse side effects, while other sources state it is not effective and should not be used.

Anti-inflammatory treatments

Topical

s are effective in short-term treatment of seborrhoeic dermatitis and are as effective or more effective than antifungal treatment with

azole Azoles are a class of five-membered heterocyclic compounds containing a nitrogen atom and at least one other non-carbon atom (i.e. nitrogen, sulfur, or oxygen) as part of the ring. Their names originate from the Hantzsch–Widman nomenclature. Th ...

s. These are sometimes used for only a few weeks at a time. There is also evidence for the effectiveness of topical calcineurin inhibitors like

tacrolimus Tacrolimus, sold under the brand name Prograf among others, is an immunosuppressive drug. After Allotransplantation, allogenic organ transplant, the risk of organ Transplant rejection, rejection is moderate. To lower the risk of organ rejectio ...

and pimecrolimus as well as lithium salt therapy. Calcineurin inhibitors were also effective in reducing the growth of Malassezia, offering two routes by which they may treat seborrhoeic dermatitis. Medications such as calcineurin inhibitors should not be used in individuals with seborrhoeic dermatitis who are immune-compromised because they cause further immune suppression. Oral immunosuppressive treatment, such as with

prednisone Prednisone is a glucocorticoid medication mostly used to immunosuppressive drug, suppress the immune system and decrease inflammation in conditions such as asthma, COPD, and rheumatologic diseases. It is also used to treat high blood calcium ...

, has been used in short courses for seborrhoeic dermatitis, as a last resort due to its potential side effects.

Antihistamines

Antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provides ...

s are used primarily to reduce

itching An itch (also known as pruritus) is a sensation that causes a strong desire or reflex to scratch. Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both ...

, if present. However, research studies suggest that some antihistamines have anti-inflammatory properties.

Keratolytics

Keratolytic Keratolytic () therapy is a type of medical treatment to remove warts, calluses and other lesions in which the epidermis produces excess skin. In this therapy, acidic topical medicines, such as Whitfield's ointment or Jessner's solution, are a ...

s help the skin via exfoliation of built-up skin flakes and thereby remove scale. They are applied topically to the affected area. Keratolytics include

urea Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest am ...

salicylic acid Salicylic acid is an organic compound with the formula HOC6H4COOH. A colorless (or white), bitter-tasting solid, it is a precursor to and a active metabolite, metabolite of acetylsalicylic acid (aspirin). It is a plant hormone, and has been lis ...

coal tar Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It is a type of creosote. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoria ...

lactic acid Lactic acid is an organic acid. It has the molecular formula C3H6O3. It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as wel ...

, pyrithione zinc and propylene glycol.

Coal tar Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It is a type of creosote. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoria ...

shampoo formulations can be effective. Although no significant increased risk of cancer in human treatment with coal tar shampoos have been found, caution is advised since coal tar is

in animals, and heavy human occupational exposures do increase cancer risks.

Other treatments

Isotretinoin Isotretinoin, also known as 13-''cis''-retinoic acid and sold under the brand name Accutane among others, is a medication used to treat skin diseases like harlequin-type ichthyosis, and lamellar ichthyosis, and severe cystic acne or moderat ...

, a sebosuppressive agent, may be used to reduce sebaceous gland activity as a last resort in refractory disease. However, isotretinoin has potentially serious side effects, and few patients with seborrhoeic dermatitis are appropriate candidates for therapy. * Topical 0.75% and 1%

Metronidazole Metronidazole, sold under the brand name Flagyl and Metrogyl among others, is an antibiotic and antiprotozoal medication. It is used either alone or with other antibiotics to treat pelvic inflammatory disease, endocarditis, and bacterial vagino ...

* Topical 4%

nicotinamide Nicotinamide (International nonproprietary name, INN, British Approved Name, BAN ) or niacinamide (United States Adopted Name, USAN ) is a form of vitamin B3, vitamin B3 found in food and used as a dietary supplement and medication. As a suppl ...

* Topical sulfacetamide * Tea tree oil * Cannabidiol shampoo * Frequent washing to avoid the build-up of scale, especially on the scalp, but while avoiding overly drying the skin * Avoiding damaging skin with harsh grooming or chemical irritants * Bicalutamide, an antiandrogen, has been observed in one patient to have potentially been the cause of seborrheic dermatitis relief. However, even if it were demonstrated that bicalutamide or any other antiandrogen is a treatment, it is not recommended due to side effects and price.

Phototherapy

Another option is natural and artificial

UV radiation Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of t ...

since it can inhibit the growth of '' Malassezia'' yeast. Some recommend

photodynamic therapy Photodynamic therapy (PDT) is a form of phototherapy involving light and a photosensitizing chemical substance used in conjunction with molecular oxygen to elicit cell death ( phototoxicity). PDT is used in treating acne, wet age-related macula ...

using

UV-A Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of the ...

and UV-B laser or red and blue

LED A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresp ...

light to inhibit the growth of ''Malassezia'' fungus and reduce seborrhoeic inflammation.

Outcome

Seborrhoeic dermatitis is generally a chronic and recurring condition. Individuals may have the condition for several weeks to months, but it may also last years or their lifetime. There may be periods of relapse and worsening.

Epidemiology

Seborrhoeic dermatitis affects 1 to 5% of the general population. It is slightly more common in men, but affected women tend to have more severe symptoms. The condition usually recurs throughout a person's lifetime. Seborrhoeic dermatitis can occur in any age group but often occurs during the first three months of life then again at puberty and peaks in incidence at around 40 years of age. It can reportedly affect as many as 31% of older people. Infants may also have this condition, though it is typically milder, and is referred to as

. Seborrhoeic dermatitis is more common in African-Americans. Severity is worse in dry climates as well as hot weather, as dry skin can exacerbate the condition.

COVID-19 Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the coronavirus SARS-CoV-2. In January 2020, the disease spread worldwide, resulting in the COVID-19 pandemic. The symptoms of COVID‑19 can vary but often include fever ...

related mask usage may also cause or exacerbate facial seborrhoeic dermatitis. Individuals who are immunocompromised have an increased risk of seborrhoeic dermatitis. Conditions that are associated with increased rates of seborrhoeic dermatitis include individuals with HIV,

Hepatitis C Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection period, people often have mild or no symptoms. Early symptoms can include ...

, alcoholic pancreatitis,

, and alcohol abuse. Seborrhoeic dermatitis is common in people with alcoholism, between 7 and 11 percent, which is twice the normal expected occurrence.

References

External links

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