| Seborrhoeic dermatitis | |
|---|---|
| Other names | Sebopsoriasis, seborrhoeic eczema, pityriasis capitis[1] |
 | |
| Seborrhoeic dermatitis of the face | |
| Specialty | Dermatology |
| Symptoms | Flaking, dry or greasy, red, itchy, and inflamed skin[2][3] |
| Duration | Several weeks to lifelong[4] |
| Causes | Multiple factors[4] |
| Risk factors | Stress, dry skin, winter,poor immune function,Parkinson disease[4] |
| Diagnostic method | Based on symptoms[4] |
| Differential diagnosis | Psoriasis,atopic dermatitis,tinea capitis,rosacea,systemic lupus erythematosus[4] |
| Treatment | Humidifier |
| Medication | Antifungal cream,anti-inflammatory agents,coal tar,phototherapy[3] |
| Frequency | ~5% (adults),[4] ~10% (babies)[5] |
Seborrhoeic dermatitis (also spelled seborrheic dermatitis in American English) is a long-termskin disorder.[4] Symptoms include flaky, scaly, greasy, and occasionally itchy and inflamed skin.[2][3] Areas of the skin rich inoil-producingglands are often affected including thescalp, face, and chest.[4] It can result in social or self-esteem problems.[4] In babies, when the scalp is primarily involved, it is calledcradle cap.[2] Mild seborrhoeic dermatitis of the scalp may be described in lay terms asdandruff due to the dry, flaky character of the skin.[6] However, as dandruff may refer to any dryness or scaling of the scalp, not all dandruff is seborrhoeic dermatitis.[6] Seborrhoeic dermatitis is sometimes inaccurately referred to asseborrhoea.[4]
The cause is unclear but believed to involve a number of genetic and environmental factors.[2][4] Risk factors for seborrhoeic dermatitis includepoor immune function,Parkinson's disease, andalcoholic pancreatitis.[4][6] The condition may worsen withstress or during the winter.[4]Malassezia yeast is believed to play a role.[6] It is not a result of poorhygiene.[7] Diagnosis is typically clinical and based on the symptoms present.[4][8] The condition is notcontagious.[9]
The typical treatment is topicalantifungal cream andanti-inflammatory agents.[3] Specifically,ketoconazole orciclopirox are effective.[10] Seborrhoeic dermatitis of the scalp is often treated with shampoo preparations ofketoconazole,zinc pyrithione, andselenium, although the latter has been partly discontinued due to concerns of selenium in higher concentrations beingcarcinogenic.[11]
The condition is common in infants within the first three months of age or adults aged 30 to 70 years.[2][4][5] It tends to affect more males.[12] Seborrhoeic dermatitis is more common in African Americans, among immune-compromised individuals, such as those with HIV, and individuals withParkinson's disease.[11][12]
.jpg)
Seborrhoeic dermatitis typically appears as dry, white, flaky skin. The flakes can be fine, loose, and diffuse or thick and adherent.[11][8] Additionally, flakes can appear yellow and oily or greasy.[8][12] 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.[8]
Seborrhoeic dermatitis of the scalp can appear similarly to dandruff.[11] When the scalp is affected, there can be associated temporary hair loss.[11] Such hair loss varies in appearance from diffuse thinning to patchy areas of hair loss.[11] On close inspection, the locations where hair has thinned may have broken stubs of hair and pustules around the hair follicles.[11] Individuals with more pigmented skin tones may experience increased or decreased skin pigmentation in affected areas.[12]
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.[11]
Seborrhoeic dermatitis' symptoms are typically mild and appear gradually but are often persistent, lasting weeks to years.[8][11][13] Individuals with seborrhoeic dermatitis are subject to recurrent bouts and it may be a lifelong condition.[8] Seborrhoeic dermatitis can also occur quickly and severely in patients withHuman Immunodeficiency Virus (HIV). This is sometimes the first indication of HIV.[12]
The cause of seborrhoeic dermatitis has not been fully clarified.[1][14]
In addition to the presence ofMalassezia, genetic, environmental, hormonal, and immune-system factors are necessary for and/or modulate the expression of seborrhoeic dermatitis.[15][16] The condition may be aggravated by illness, psychological stress, fatigue, sleep deprivation, change of season, and reduced general health.[17]
The condition is thought to be due to a localinflammatory response to overgrowth byMalasseziafungi species insebum-producingskin areas including thescalp,face,chest,back,underarms, andgroin.[3][14] This is based on observations of high counts ofMalassezia species in skin affected by seborrhoeic dermatitis and on the effectiveness ofantifungals in treating the condition.[14] Species ofMalassezia implicated in Seborrhoeic dermatitis includeM. furfur (formerlyPityrosporum ovale),M. globosa,M. restricta,M. sympodialis, andM. slooffiae.[3]
Malassezia appears to be a significant factor in seborrhoeic dermatitis, but it is thought that other factors are necessary for the presence ofMalassezia to result in seborrhoeic dermatitis.[14] For example, summer growth ofMalassezia in the skin alone does not result in seborrhoeic dermatitis.[14] Besides antifungals, the effectiveness ofanti-inflammatory drugs, which reduce inflammation, andantiandrogens, which reducesebum production, provide further insights into thepathophysiology of seborrhoeic dermatitis.[3][18][19]
Several bacteria, includingPropionibacterium species andStaphylococcus aureus, have been shown to have some level of interaction with seborrhoeic dermatitis, though their exact impact is not known.[20][12]
Seborrhoeic dermatitis-like eruptions are also associated with pyridoxine (vitamin B6) and riboflavin (vitamin B2) deficiency.[21][8] In children and babies, issues withΔ6-desaturaseenzymes[17] have been correlated with increased risk.
Those withimmunodeficiency (especiallyinfection withHIV) and withneurological disorders that may impact immune system function such asParkinson's disease (for which the condition is anautonomic sign) andstroke are particularly prone to it.[22][unreliable medical source?]
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 lowhumidity and lowtemperature are responsible for the high frequency of seborrheic dermatitis.[23] Others suggest hot environments may also worsen seborrhoeic dermatitis.[12] Yet another described that high humidity and low UV exposure are culpable.[24] Dry skin and an impaired skin barrier contribute to the condition.[12][20] It is likely that climate and weather variations affect the water and lipid content of skin.[20]
Seborrhoeic dermatitis is a complex condition with many interacting factors that are not yet fully explained.[14] In general, the major factors that influence the development and severity includeMalassezia yeast present on and in the skin, skin production of oily sebum, and a subsequent inflammatory response againstMalassezia and their byproducts.[12] 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.[14][12]
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.[14] An alternative explanation is an increase in sebum production feeding an increase in theMalassezia population that instigates inflammation; the inflammation then causes cellular changes that damage the skin barrier. This barrier disruption then encourages additionalMalassezia growth and inflammation and again worsens skin barrier function.[12]
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.[8] However, seborrhoeic dermatitis may also be diagnosed with additional testing. The least invasive test is a visual inspection in the clinic using aWood's Lamp.[11] AKOH test can also be used, where skin scraping of the affected skin may also be taken and prepared withpotassium hydroxide (KOH) and visualized under a microscope to look forMalassezia or other microbiological cells. Additionally, afungal culture of the affected skin may be taken to attempt to grow and identify the causative organism.[11]
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.[8][11]
A variety of different types of medications can reduce symptoms of seborrhoeic dermatitis.[3] These include certainantifungals,anti-inflammatory agents likecorticosteroids andnonsteroidal anti-inflammatory drugs,antiandrogens, andantihistamines, among others.[3][1] Treatments must take into consideration potential side effects, especially with long-term use given the chronic nature of seborrhoeic dermatitis.[neutrality isdisputed] Initial therapy is usually a topical preparation with an agreeable side effect profile.[12]
Regular use of anover-the-counter or prescriptionantifungalshampoo orcream is a common treatment. The topical antifungal medicationsketoconazole andciclopirox have the best evidence.[10] Ketoconazole should be used twice per week.[8] Shampoo or soap containingzinc pyrithione orselenium disulfide is also used.[8] These options should be used daily but may also be used in conjunction with a ketoconazole shampoo regimen on alternate days.[8] It is unclear if other antifungals are equally effective, as this has not been sufficiently studied.[10] Antifungals that have been studied and found to be effective in the treatment of seborrhoeic dermatitis includeketoconazole,fluconazole,miconazole,bifonazole,sertaconazole,clotrimazole,flutrimazole,ciclopirox,terbinafine,butenafine,selenium disulfide, andlithium salts such aslithium gluconate andlithium succinate.[10][3]
Topicalclimbazole appears to have little effectiveness in the treatment of seborrhoeic dermatitis.[10] Systemic therapy with oral antifungals includingitraconazole,fluconazole,ketoconazole is effective, but adverse side effects have been documented forfluconazole andketoconazole, with the latter not recommended for use, whileitraconazole, with its good safety profile, is the most commonly prescribed.[3]Terbinafine is said to be effective, but with adverse side effects, while other sources state it is not effective and should not be used.[3][11]
Topicalcorticosteroids are effective in short-term treatment of seborrhoeic dermatitis and are as effective or more effective than antifungal treatment withazoles. These are sometimes used for only a few weeks at a time.[11][additional citation(s) needed] There is also evidence for the effectiveness of topicalcalcineurin inhibitors liketacrolimus andpimecrolimus as well aslithium salt therapy.[25] Calcineurin inhibitors were also effective in reducing the growth of Malassezia, offering two routes by which they may treat seborrhoeic dermatitis.[24] Medications such as calcineurin inhibitors should not be used in individuals with seborrhoeic dermatitis who are immune-compromised because they cause further immune suppression.[11]
Oral immunosuppressive treatment, such as withprednisone, has been used in short courses for seborrhoeic dermatitis, as a last resort due to its potential side effects.[26]
Antihistamines are used primarily to reduceitching, if present. However, research studies suggest that some antihistamines have anti-inflammatory properties.[27]
Keratolytics help the skin via exfoliation of built-up skin flakes and thereby remove scale. They are applied topically to the affected area. Keratolytics includeurea,salicylic acid,coal tar,lactic acid, pyrithione zinc and propylene glycol.[24]Coal tar shampoo formulations can be effective.[8][24] Although no significant increased risk of cancer in human treatment with coal tar shampoos have been found, caution is advised since coal tar iscarcinogenic in animals, and heavy human occupational exposures do increase cancer risks.[28]
Another option is natural and artificialUV radiation since it can inhibit the growth ofMalassezia yeast.[31] Some recommendphotodynamic therapy usingUV-A andUV-B laser or red and blueLED light to inhibit the growth ofMalassezia fungus and reduce seborrhoeic inflammation.[31][32][33]
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.[11][8]
Seborrhoeic dermatitis affects 1 to 5% of the general population.[1][34][35] It is slightly more common in men, but affected women tend to have more severe symptoms.[35] The condition usually recurs throughout a person's lifetime.[36] Seborrhoeic dermatitis can occur in any age group[36] but often occurs during the first three months of life then again at puberty and peaks in incidence at around 40 years of age.[37][20] It can reportedly affect as many as 31% of older people.[35] Infants may also have this condition, though it is typically milder, and is referred to ascradle cap.[12] Seborrhoeic dermatitis is more common in African-Americans.[12]
Severity is worse in dry climates[36] as well as hot weather, as dry skin can exacerbate the condition.[12]COVID-19 related mask usage may also cause or exacerbate facial seborrhoeic dermatitis.[12]
Individuals who are immunocompromised have an increased risk of seborrhoeic dermatitis.[12] Conditions that are associated with increased rates of seborrhoeic dermatitis include individuals with HIV,Hepatitis C, alcoholic pancreatitis,Parkinson's disease, and alcohol abuse.[12] Seborrhoeic dermatitis is common in people with alcoholism, between 7 and 11 percent, which is twice the normal expected occurrence.[38]
Media related toSeborrhoeic dermatitis at Wikimedia Commons
Authority control databases: National |
|---|
