Seborrheic Dermatitis Risk Factors: Altitude and UV Radiation

Altitude and UV Radiation

Seborrheic dermatitis is a common condition that can affect the scalp (where it causes an itchy, red and greasy scalp) but can also affect the eyebrows, face, chest as well as other areas too. A yeast known as Malassezia has an important role. 
There are many factors that are known to increase one’s risk of developing seborrheic dermatitis. For example, stress, age, heat, humidity, depression, Parkinson’s disease, head injury, neurological disease, HIV and UV radiation all increase the risk of SD. Other risks include acne, lighter skin, higher body fat content.

It’s clear that immunosuppression can affect SD. This is especially true in patients with HIV/AIDS. But we also see the effect of immunosuppression with ultraviolet radiation which is also a form of immunosuppression. Studies have shown that some individuals experience flares with intense UV radiation exposure.

High altitude may be a risk factor for seborrheic dermatitis.

An interesting study conducted in 2000 looked at the risk of SD in 283 mountain guides from 3 different counties who have a high occupational exposure to UV radiation. 16.3% mountain guides when examined clinically were found to have SD and these rates were similar across the 3 countries. This number is higher than the 3-5 % rate of SD in the general population. These studies suggested that UV-induced immunosuppression due to occupational sun exposure as a pathogenetic factor in SD. 

Reference

Moehrle M, et al. High prevalence of seborrhoeic dermatitis on the face and scalp in mountain guides.
Dermatology. 2000

Seborrheic dermatitis of the Frontal Hairline

Seborrheic dermatitis

Seborrheic dermatitis is a flaky scalp and skin condition that affects 5 to 10 % of people. Its less severe form is called dandruff and affects 50 % of the world at some point.

Seborrheic dermatitis is caused in part by a yeast known as Malassezia although a variety of factors are now understood to contribute. Seborrheic dermatitis can affect many areas of the body including the scalp, forehead, eyebrows, nose, chest, back. A variant of seborrheic dermatitis that affects the hairline and extends onto the forehead is known as "corona seborrheica."

For more information, please see Seborrheic Dermatitis - Handout for Patients 

Seborrheic dermatitis

Risk Factors for Seborrheic dermatitis

Seborrheic dermatitis is an itchy flaky scalp condition that closely resembles ordinary "dandruff." Many consider seborrheic dermatitis to be an inflammatory variant of dandruff.

The condition is now understood to be due to a yeast known as Malassezia. Factors such as age, stress, heat, humidity, ultraviolet radiation, neurological disease, depression. HIV/AIDS, Parkinson's disease and medications are all risk factors.

Can drugs cause or exacerbate seborrheic dermatitis?

Can drugs cause or exacerbate seborrheic dermatitis? 

Seborrheic dermatitis is red, scaly and sometimes itchy scalp and skin condition that closely resembles dandruff. The condition is extremely common and affects 5 % or more of the population.

There are a variety of well known factors that increase the risk of seborrheic dermatitis including depression, neurological conditions, alcoholism, stress, HIV/AIDS, organ transplantation and advanced age (over 60). 

Drugs are also potential causes of either worsening or inducing seborrheic dermatitis. The anti-cancer drugs are well known causes of seborrheic dermatitis like eruptions. Examples include dasatinib, gefitinib, sorafenib, sunitinib, vemurafenib, 5-FU, Erlotinib, cetuximab, IL-2, and interferon-α. I often advise a scalp biopsy in many of these cancer drug associated seborrheic dermatitis-like presentations as many are actually forms of scarring alopecia (ie EGFR inhibitors). 

Other drugs causing a seborrheic dermatitis-like eruption include griseofulvin, cimetidine, lithium, buspirone, haloperidol, lithium, methyldopa, gold, ethionamide, methoxsalen, methyldopa, phenothiazines, psoralens, stanozolol, and thiothixene.

Seborrheic Dermatitis: What causes it and how can we treat it.

Seborrheic Dermatitis: What causes it and how do we treat it?

Seborrheic dermatitis is a red, scaly, skin and scalp condition that affects both children and adults. The condition is extremely common. Estimates suggest that up to 3-5 % of the world is affected by the condition. Infants can be affected by seborrheic dermatitis, and this is typically called 'cradle cap.' During pre-pubertal years the incidence of seborrheic dermatitis reduces significantly until it spikes again in adolescence. Adults can be affected and the incidence increases again in the 60s and 70s. 

Seborrheic dermatitis is thought to be caused by a variety of factors. However, central to all these factors is the presence of a yeast known as Malassezia and some local or systemic alteration in the immune system. Malazzesia yeast are thought to help metabolize certain types of fats in the skin from non irritating to irritating and inflammatory fatty acids that cause inflammation. It's clear that getting rid of these yeast helps control the symptoms and signs of seborrheic dermatitis. Most individuals with seborrheic dermatitis have a healthy immune system. However, it's clear that there is some alteration in the skin immune system that prevents these individuals from eradicating the Malazzesia yeast. 

Risk Factors for Seborrheic Dermatitis

Some patients develop seborrheic dermatitis for no clear reason. These individuals likely have an underlying predisposition to the condition. However, it is now clear that there are a number of risk factors for seborrheic dermatitis, including neurological disease (Parkinson's disease, traumatic brain injury), depression, organ transplantation, HIV/AIDS, alcoholic pancreatitis, intense stress.

 

Signs and Symptoms of Seborrheic dermatitis

Seborrheic dermatitis can affect both the scalp and the skin. Patients may be completely asymptomatic or notice varying degrees of scalp itching, redress, flaking and scaling. The scalp may become greasy with patients feeling that more frequent shampooing just makes things feel better. The eyebrows can also be affected by redness and flaking. Many patients with seborrheic dermatitis have red flaky patches arund the nose, on the mid-chest and even back.

 

Treatment of Seborrheic Dermatitis

There is no cure for seborrheic dermatitis but there are treatments that can help reduce the frequency and severity of flares. In other words, appropriate treatment, can help make it appear that patients have minor disease or no disease at all. However, periodic use of anti-fungal and anti-inflammatory agents may be needed to keep the condition under control. 

 There are a variety of treatments of Seborrheic dermatitis. Eradicating the Malasezia yeast appears to be important in the treatment. For this reason, I generally recommend use of various anti-dandruff shampoos including those containing zinc pyrithione, selenium sulphide, ketoconazole, and ciclopirox. These should be left on the scalp for 1-5 minutes depending on the specific patient's scalp. Anti-dandruff shampoos can be drying, and so careful monitoring is needed to determine how best to use these for any given patent. 

A variety of natural products can also help seborrheic dermatitis. Tea tree oil is among the most helpful of the natural products and is available in a variety of shampoo formulations. 

Corticosteroids can sometimes be used but are generally not first line agents for most with mild cases of seborrheic dermatitis. However, use of corticosteroid shampoo (such as Clobex) or mild corticosteroid lotions (including periodic use of betamethasone valerate lotion of foam) during times of flares can help many to achieve remission and feel better. 

Oral agents including retinoids (isotretinoin) and oral anti-fungal agents (itraconazole) are reserved for more challenging cases of seborrheic dermatitis that is unresponsive to conventional treatments. 

Shampoos for Seborrheic dermatitis and Dandruff

Shampoos for Treating Seborrheic and Dandruff 

A variety of shampoos are available for treating dandruff and seborrheic dermatitis. The following is a helpful list we provide our patients. It includes both sulphate free and sulphate containing shampoos. To download the complete handout, click here. 

Anti-Dandruff Shampoos

Sulphate Free Anti-Dandruff Shampoos

Tea tree oil shampoo for treating seborrheic dermatitis: What is the evidence?

A number of shampoos have emerged on the market containing tea tree oil. I sometimes recommend it to patients who are looking for more natural products to treat their seborrheic dermatitis.

Of course, I would not recommend a treatment unless it was backed up by some kind of reasonably conducted study. A study from 2002 by Satchell and colleagues examined the benefits of a 5% tea tree oil shampoo compared to a placebo shampoo is 126 males and females with seborrheic dermatitis.

Patients used either shampoo daily for 4 weeks. What were the results? Well, individuals using tea tree oil had a reduction in severity of the seborrheic dermatitis and less itching and greasiness.

Conclusion

There is evidence to support use of tea tree oil as a treatment for seborrheic dermatitis. More studies are needed and to evaluate how tea tree oil compares with standard seborrheic dermatitis treatments such as ketoconazole, zinc pyrithione and selenium sulphide.

Reference

Satchell et al Journal of American Academy of Dermatology 2002.

Psoriasis + Seborrheic Dermatitis

Sebopsoriasis

Sebopsoriasis is a scaly scalp condition with features of both psoriasis and seborrheic dermatitis.

Many patients with psoriasis have overgrowth of Malassezia yeast which are known to play a role in seborrheic dermatitis. Some evidence suggests that Malassazia yeast may even be involved in the pathogenesis of psoriasis. Patients with sebopsoriasis often have a family history of psoriasis or seborrheic dermatitis. Lesions are less silvery white than classic psoriasis bit more defined and deeply red than classic seborrheic dermatitis. Scale is often thicker in areas than seborrheic dermatitis.

How often should I use my shampoo for treating seborrheic dermatitis?

There are several good shampoos for treating seborrheic dermatitis. These include shampoos containing ingredients such as ketoconazole, selenium sulphide, zinc pyrithione and ciclopirox.

Most of the time, I start my patients on 3 times weekly use of these shampoos for anywhere from 2-5 minutes. Over time (and depending on response) we go down to 1-2 times weekly and sometimes every second week.  Please see a dermatologist to carefully review what is appropriate in your case.

Not everyone with seb derm responds to these shampoos. In such cases addition of a corticosteroid for a short period of time or use of an oral antifungal or oral retinoid may be appropriate.

Is It possible for seb derm to cause hair loss?

Seborrheic Dermatitis and Hair Loss

Seborrheic dermatitis and the closely related condition "dandruff" are two scaly scalp conditions that are common in the general population. I'm often asked if these conditions can cause hair loss. It is a fact (not a speculation) that seborrheic dermatitis can cause an individual to experience increased hair shedding (telogen effluvium). This has been shown many times in various studies. 

Dr Pierard- Franchimont and colleagues have done very interesting research in the area of seborrheic dermatitis and dandruff. They showed about 10 years ago that the more seborrheic dermaitits a person has, the more shedding (telogen effluvium) a person will experience. This is important information to know because it tells us that individuals with severe seborrheic dermatitis are likely to have a severe telogen effluvium. Dr Pierard Franchimont and others have also shown data that the inflammatory reaction can even accelerate male balding in some cases making it important to aggressively treat seborrheic dermatitis in patients with hair loss. 

There is no doubt about the relationship between seborrheic dermatitis and shedding. Companies that manufacture dandruff shampoos study shedding patterns to determine if their shampoo is working. Anti-dandruff shampoos can reduce shedding. 

In summary, seborrheic dermatitis can certainly cause a telogen effluvium. This photo shows the scalp of a patient with moderate seborrheic dermatitis. Numerous upright regrowing hairs (URH) are seen, which is a typical sign of a hair cycling abnormality (telogen effluvium).

Reference

Piérard-Franchimont C, et al. Dandruff-associated smouldering alopecia: a chronobiological assessment over 5 years. Clin Exp Dermatol. 2006.

Seborrheic Dermatitis & Dandruff

Malassezia Yeast Have Key Role

Continuing with our theme this week of fungus, we will focus on seborrheic dermatitis and dandruff. These are extremely common scaly scalp conditions. A fungus known as "Malassezia" is now believed to play a key role in seborrheic dermatitis and dandruff. 
Most human beings are covered in Malassezia. It's just part of being human and living on planet Earth.

Only in a minority of people do these fungi cause any sort of health problems. 
Malassezia were originally discovered by the French scientist Louis Charles Malassez in the late 1800's. There are now recognized to be 14 types of Malassezia. For trivia lovers, Malassezia globosa (mainly) and Malassezia restricta (less so) are the most common causes of seborrheic dermatitis. 

Malassezia are difficult to culture so one can not simply send samples off to the lab. These fungi need fats and lipids to survive - so they live in areas of the body rich in sebaceous (oil) glands such as the scalp and face.

Anti-dandruff shampoos are generally quite effective in killing these fungi. Common ingredients in shampoos include ketoconazole, zinc pyrithione, selenium sulphide and ciclopirox.

Seborrheic Dermatitis and Scarring: Seborrheic Folliculitis

Can a seborrheic dermatitis lead to a scarring alopecia-like phenomenon?

In 2015, Australian researchers reported an interesting article in the Australasian Journal of Dermatology suggesting the possibility of a low grade folliculitis which ultimately leads to development of a scarring alopecia.

The study described 56 patients (35 female and 21 male, age range late teens to late 70s) with a seborrheic dermatitis like presentation that was associated with a scarring alopecia. They termed the condition “seborrheic folliculitis.” These patients presented clinically with a red, itchy scalp (some patients) along with a diffuse or patchy dandruff like presentation. Shedding of telogen hairs was a feature.

Perifollicular parakeratotic scale was noted along with variable scalp erythema, and perifollicular prominence. Dermoscopy showed perifollicular hyperkeratosis and increased vascularity in the perifollicular areas. Pathology showed an absence of lichenoid change and there was a mild interfollicular fibrosis much like is seen in folliculitis decalvans (although too mild for typical folliculitis decalvans).  Spongiosis of the follicular epitheilium was noted along with a perivascular and perifollicular infiltrate of lymphocytes. Treatment was successful in many patients with tar shampoos and doxycycline. 

Here is one such example of a "seborrheic folliculitis" in a patient with androgenetic alopecia. Scarring is present and focal areas devoid of hair can be found on the scalp.

Reference

Pitney L et al. Is seborrhoeic dermatitis associated with a diffuse, low-grade folliculitis and progressive cicatricial alopecia? Australas J Dermatol 2016; 57(3):e105-7.