26: Seborrheic Dermatitis

Question 1

What are the general features of seborrheic dermatitis?

Answer 1

Seborrheic dermatitis is characterized by erythematous, scaly patches on sebaceous gland-rich sites (scalp, face, upper trunk, intertriginous areas), ranging from mild pinkish scaling to solid adherent crusts. It is associated with itching and burning, leading to psychosocial distress, affects all races and ethnic groups with a worldwide distribution, and has a higher incidence and more severe forms in AIDS patients and individuals with certain neurologic conditions.

Question 2

What is infantile seborrheic dermatitis and its characteristics?

Answer 2

Infantile seborrheic dermatitis affects babies as young as 2 weeks, with peak incidence at 3 months. It typically resolves within the first 6-12 months of life and presents as a nonpruritic skin eruption affecting the frontal or vertex areas of the scalp and central face, characterized by dry, thick, adherent, and flaking scale. It may be accompanied by an erythematous rash on intertriginous folds of the trunk and extremities, commonly known as ‘cradle cap’.

Question 3

What are the clinical features of Leiner Disease?

Answer 3

Leiner Disease is characterized by desquamative erythroderma in infants, sparse hair, frequent loose stools, and failure to thrive. It is considered an umbrella phenotype rather than a single-disease entity, with congenital or acquired deficiencies of C3, C5, and phagocytic activity leading to defective opsonization of yeast and bacteria. Secondary bacterial infections can be life-threatening, and treatment includes IV hydration, temperature regulation, and antibiotics.

Question 4

What is Pityriasis Amiantacea and its characteristics?

Answer 4

Pityriasis Amiantacea is an inflammatory condition of the scalp characterized by large plates of thick, silvering scale that are firmly adherent to both the scalp and hair tufts. It is also known as asbestos-like scalp and can be referred to as tinea asbestina, tinea amiantacea, keratosis follicularis amiantacea, and porrigo amiantacea.

Question 5

What are the common clinical features of seborrheic dermatitis in adolescents and young adults?

Answer 5

Seborrheic dermatitis in adolescents and young adults typically presents as a chronic and relapsing pattern with erythematous, scaly patches on sebaceous gland-rich sites (scalp, face, upper trunk), itching and burning sensations, psychosocial distress due to cosmetic concerns, and increased activity of sebaceous glands due to hormonal effects.

Question 6

How does infantile seborrheic dermatitis typically present in infants, and what is its expected course?

Answer 6

Infantile seborrheic dermatitis usually presents as a nonpruritic skin eruption affecting babies as young as 2 weeks, with peak incidence at 3 months, characterized by dry, thick, adherent, and flaking scale. It may be accompanied by an erythematous rash on intertriginous folds and is commonly referred to as ‘cradle cap’, typically resolving within the first 6-12 months of life.

Question 7

What are the key differences between seborrheic dermatitis and Leiner disease in infants?

Answer 7

Key differences include:

Feature | Seborrheic Dermatitis | Leiner Disease |
|——————————-|——————————————-|———————————————|
| Presentation | Erythematous, scaly patches | Desquamative erythroderma |
| Hair | Normal or sparse hair | Sparse hair |
| Stool | Normal | Frequent loose stools |
| Failure to Thrive | Not typically present | Commonly present |
| Treatment | Topical treatments | IV hydration, antibiotics essential |

Question 8

What are the clinical implications of pityriasis amiantacea, and how does it present?

Answer 8

Pityriasis amiantacea presents as an asbestos-like scalp condition, characterized by large plates of thick, silvering scale firmly adherent to both the scalp and hair tufts. Clinical implications include potential for secondary infections due to compromised skin integrity and may require specific treatments to manage inflammation and scaling.

Question 9

What is the likely diagnosis for a 35-year-old male with erythematous, scaly patches on his scalp and face and a history of Parkinson’s disease?

Answer 9

The likely diagnosis is seborrheic dermatitis (SD). SD is more severe in patients with Parkinson’s disease due to facial immobility leading to sebum accumulation and potential neurotransmitter abnormalities.

Question 10

What is the diagnosis for an infant with a nonpruritic skin eruption affecting the scalp and central areas of the face, accompanied by thick, adherent flaking scales?

Answer 10

The diagnosis is infantile seborrheic dermatitis (ISD). Unlike adult SD, ISD is nonpruritic, self-limited, and resolves by 6-12 months of age.

Question 11

What are the common associations of Seborrheic Dermatitis (SD) with HIV and AIDS?

Answer 11

Seborrheic Dermatitis arises in more extensive and refractory patterns in up to 83% of HIV-seropositive and AIDS patients. It may initially present as a butterfly-like rash seen in Systemic Lupus Erythematosus (SLE) and is associated with a reduction in T-cell function, worsening as the CD4+ count decreases.

Question 12

What factors contribute to the etiology and pathogenesis of Seborrheic Dermatitis (SD)?

Answer 12

The etiology of SD is multifactorial, involving several endogenous and exogenous factors, including the role of sebaceous glands, the immunologic status of patients, Malassezia as a normal skin flora, and seasonal fluctuations and sun exposure.

Question 13

How does the immune response relate to Seborrheic Dermatitis (SD)?

Answer 13

In immunosuppressed patients, SD is more common. Studies show increased production of interleukins (IL-1, IL-4, IL-12, TNF, IFN-γ) in lesions, and inflammatory genes are expressed in uninvolved skin, suggesting predisposing factors for inflammation in SD patients.

Question 14

What microbial effects are associated with Seborrheic Dermatitis (SD)?

Answer 14

Malassezia, a normal skin flora, is important in SD. Common lesions of SD are related to sebaceous glands where Malassezia colonizes, and antifungal medications have therapeutic effects against SD.

Question 15

What lipid and host susceptibility factors are associated with Seborrheic Dermatitis (SD)?

Answer 15

Individual susceptibility to SD is linked to a disrupted epidermal barrier, allowing irritating metabolites to penetrate. Irritating free fatty acids (FFAs) can mediate dandruff-like flaking in susceptible individuals.

Question 16

What are the associations between seborrheic dermatitis (SD) and HIV/AIDS, particularly regarding T-cell function and disease progression?

Answer 16

Seborrheic dermatitis (SD) arises in more extensive and refractory patterns in up to 83% of HIV-seropositive and AIDS patients, associated with a reduction in T-cell function and worsening as the CD4+ count decreases.

Question 17

How does the immunologic status of patients influence the susceptibility to seborrheic dermatitis (SD)?

Answer 17

The immunologic status of patients significantly influences susceptibility to SD, being more commonly seen in individuals with underlying diseases such as AIDS and Parkinson’s disease.

Question 18

What role does Malassezia play in the pathogenesis of seborrheic dermatitis (SD)?

Answer 18

Malassezia, a normal skin flora, is suggested to be important in the pathogenesis of SD, with common lesions related to sebaceous glands where Malassezia preferentially colonizes.

Question 19

What are the potential microbial effects of Malassezia in patients with seborrheic dermatitis (SD)?

Answer 19

Malassezia can induce inflammation in SD patients by colonizing sebaceous glands, producing lipase and phospholipase, and disturbing protective skin barriers.

Question 20

How do lipid and host susceptibility factors contribute to the development of seborrheic dermatitis (SD)?

Answer 20

Individual susceptibility to SD is associated with a disrupted epidermal barrier that allows irritating metabolites to penetrate, with irritating FFAs mediating dandruff-like flaking in susceptible individuals.

Question 21

A patient with seborrheic dermatitis is found to have a high concentration of Malassezia furfur. How does this contribute to the disease?

Answer 21

Malassezia furfur disturbs protective skin barriers and induces inflammation, contributing to the pathogenesis of seborrheic dermatitis.

Question 22

A patient with AIDS presents with extensive, refractory seborrheic dermatitis. What underlying immunological changes contribute to this presentation?

Answer 22

The reduction in T-cell function and decreased CD4+ count in AIDS patients contribute to the extensive and refractory nature of seborrheic dermatitis.

Question 23

A 50-year-old female presents with thick, silvering scales on her scalp that are firmly adherent to both the scalp and hair tufts. What is the condition, and what are its common associations?

Answer 23

The condition is pityriasis amiantacea, commonly associated with psoriasis (35%) and eczematous conditions like seborrheic dermatitis (SD) and atopic dermatitis (AD) (34%).

Question 24

A patient with seborrheic dermatitis has been prescribed ketoconazole shampoo. What is the rationale behind using this treatment?

Answer 24

Ketoconazole is an antifungal agent effective against Malassezia species, which are implicated in the pathogenesis of seborrheic dermatitis.

Question 25

What role does epidermal hyperproliferation play in seborrheic dermatitis (SD)?

Answer 25

Epidermal hyperproliferation is implicated in SD, leading to increased epidermal turnover and resembling psoriasis both clinically and histologically.

Question 26

How do neurotransmitter abnormalities affect the severity of seborrheic dermatitis in patients with Parkinson's disease?

Answer 26

In Parkinson's disease, the severity of SD does not correlate with sebum excretion rate; instead, sebum accumulation due to facial immobility may play a key role.

Question 27

What factors can contribute to the severity of seborrheic dermatitis?

Answer 27

Factors contributing to the severity of SD include low humidity and cold temperatures, facial trauma, certain medications, zinc or biotin deficiency, and an indoor lifestyle with less sunlight exposure.

Question 28

What are the diagnostic criteria for infantile seborrheic dermatitis (ISD)?

Answer 28

The classic diagnostic criteria for ISD include early onset (before 6 months of age), erythematous and scaling rash distributed in the scalp, diaper, or flexural areas, and relative absence of pruritus.

Question 29

What histopathological features differentiate acute and chronic seborrheic dermatitis?

Answer 29

The histopathological features include: | Type of Dermatitis | Features | |-------------------|----------| | Acute and Subacute SD | Mild psoriasiform hyperplasia, spongiotic dermatitis, scattered neutrophils, orthokeratosis with focal parakeratosis, superficial perivascular lymphohistiocytic infiltration | | Chronic SD | More intense features with minimal spongiosis, markedly dilated superficial vessels, sometimes similar to psoriasis | | HIV-associated SD | Very severe patterns |

Question 30

What role does epidermal hyperproliferation play in seborrheic dermatitis (SD) and how does it relate to psoriasis?

Answer 30

Epidermal hyperproliferation in SD indicates a disorder of increased epidermal turnover, resembling psoriasis both clinically and histologically, linked to heightened activity of calmodulin.

Question 31

How do neurotransmitter abnormalities influence the severity of seborrheic dermatitis in patients with Parkinson's disease?

Answer 31

In Parkinson's disease, the severity of SD does not correlate with sebum excretion rates; instead, facial immobility may lead to sebum accumulation, contributing to the condition.

Question 32

What factors can exacerbate seborrheic dermatitis, particularly in relation to environmental and lifestyle conditions?

Answer 32

Factors that can exacerbate seborrheic dermatitis include low humidity and cold temperatures, facial trauma, PUVA therapy, certain medications, zinc or biotin deficiency, and an indoor lifestyle with less sunlight exposure.

Question 33

What are the histopathological differences between classic seborrheic dermatitis and HIV-associated seborrheic dermatitis?

Answer 33

The histopathological differences include: | Feature | Classic Seborrheic Dermatitis | HIV-associated Seborrheic Dermatitis | |---------|------------------------------|-------------------------------------|

Question 34

What is PUVA therapy?

Answer 34

PUVA therapy is a treatment method that combines a drug called psoralen with ultraviolet A (UVA) light.

Question 35

What medications may contribute to seborrheic dermatitis?

Answer 35

Certain medications, such as griseofulvin and lithium, may contribute to seborrheic dermatitis.

Question 36

How do zinc deficiency and biotin deficiency relate to seborrheic dermatitis?

Answer 36

Zinc deficiency or biotin deficiency can lead to skin issues similar to seborrheic dermatitis.

Question 37

What lifestyle factors can exacerbate seborrheic dermatitis?

Answer 37

An indoor lifestyle with less sunlight exposure and poor hygiene can exacerbate seborrheic dermatitis.

Question 38

What are the histopathological differences between classic seborrheic dermatitis and HIV-associated seborrheic dermatitis?

Answer 38

Classic seborrheic dermatitis shows rare necrotic keratinocytes, prominent spongiosis, thin-walled vessels, and rare plasma cells. In contrast, HIV-associated seborrheic dermatitis shows many necrotic keratinocytes, sparse spongiosis, many thick-walled vessels, and increased plasma cells.

Question 39

What are the classic diagnostic criteria for infantile seborrheic dermatitis (ISD)?

Answer 39

The classic diagnostic criteria for ISD include early onset (before 6 months of age), erythematous and scaling rash in the scalp, diaper, or flexural areas, and relative absence of pruritus.

Question 40

What is the mechanism of action of azelaic acid in seborrheic dermatitis?

Answer 40

Azelaic acid acts as a cytostatic medication, targeting increased activity of calmodulin and epidermal hyperproliferation.

Question 41

What environmental factors might exacerbate seborrheic dermatitis during winter?

Answer 41

Low humidity and cold temperatures during winter can exacerbate seborrheic dermatitis.

Question 42

Why is it important for patients with seborrheic dermatitis to avoid scratching?

Answer 42

Scratching can lead to facial trauma, which exacerbates seborrheic dermatitis.

Question 43

How does zinc deficiency contribute to seborrheic dermatitis?

Answer 43

Zinc deficiency can impair skin barrier function and immune response, leading to SD-like dermatitis.

Question 44

What neurological factors might contribute to the severity of seborrheic dermatitis in patients with cerebrovascular infarcts?

Answer 44

Neurological factors such as facial immobility and neurotransmitter abnormalities can exacerbate seborrheic dermatitis.

Question 45

What dermoscopy findings suggest seborrheic dermatitis?

Answer 45

Dermoscopy may reveal twisted loops and red dots, aiding in distinguishing it from conditions like scalp psoriasis.

Question 46

What distinguishes infantile seborrheic dermatitis from other conditions?

Answer 46

The involvement of the diaper area alone is a characteristic sign of the psoriasiform type of ISD.

Question 47

What are the distinctive features of scalp psoriasis?

Answer 47

Scalp psoriasis may involve frontal hair lines and present with purpuric lesions that desquamate and ulcerate on folds and mucosal areas.

Question 48

What is the primary goal of treatment for seborrheic dermatitis in adolescents or adults?

Answer 48

The primary goal is to control symptoms rather than to cure the disease.

Question 49

What are the first-line treatment options for managing seborrheic dermatitis?

Answer 49

First-line treatment options include topical corticosteroids, topical calcineurin inhibitors, topical antifungal drugs, and keratolytics.

Question 50

What management strategies are recommended for refractory cases of seborrheic dermatitis?

Answer 50

Recommended strategies include low doses of systemic glucocorticoids, oral antifungals, oral isotretinoin, and NB UVB phototherapy.

Question 51

What are the key differential diagnoses for seborrheic dermatitis on the scalp?

Answer 51

Key differential diagnoses include psoriasis, Langerhans cell histiocytosis, scabies, and intertrigo.

Question 52

What is the recommended management for seborrheic blepharitis?

Answer 52

Management includes long-term eyelid hygiene with warm compresses, followed by topical antibiotics and corticosteroids.

Question 53

What is the dosing regimen for oral itraconazole in seborrheic dermatitis?

Answer 53

Itraconazole is prescribed at 200 mg/day for the first 7 days of the month for several months.

Question 54

What is the mechanism of action of coal tar in treating seborrheic dermatitis?

Answer 54

Coal tar reduces scaling and inflammation by slowing down epidermal turnover.

Question 55

What is the therapeutic benefit of salicylic acid shampoo?

Answer 55

Salicylic acid acts as a keratolytic, helping to remove scales and reduce flaking.

Question 56

What is the mechanism of action of ciclopirox shampoo?

Answer 56

Ciclopirox has antifungal properties, targeting Malassezia species involved in seborrheic dermatitis.

Question 57

What is the therapeutic benefit of zinc pyrithione shampoo?

Answer 57

Zinc pyrithione has antifungal and antibacterial properties, reducing Malassezia colonization and inflammation.

Question 58

What is the mechanism of action of isotretinoin in seborrheic dermatitis?

Answer 58

Isotretinoin reduces sebaceous gland activity and inflammation.

Question 59

What is the mechanism of action of ketoconazole cream?

Answer 59

Ketoconazole cream targets Malassezia species by inhibiting fungal cell membrane synthesis.

Question 60

What is a potential side effect of prolonged use of topical corticosteroids?

Answer 60

Prolonged use can lead to skin atrophy and telangiectasia.

Question 61

What is the mechanism of action of fluconazole in seborrheic dermatitis?

Answer 61

Fluconazole inhibits fungal cell membrane synthesis, targeting Malassezia species.

Question 62

What is a potential advantage of topical calcineurin inhibitors over corticosteroids?

Answer 62

Calcineurin inhibitors do not cause skin atrophy, making them suitable for long-term use.

Question 63

What is a potential advantage of NB-UVB phototherapy?

Answer 63

NB-UVB phototherapy is non-invasive and has immunomodulatory and anti-inflammatory effects.

Question 64

What is the mechanism of action of pramiconazole in seborrheic dermatitis?

Answer 64

Pramiconazole inhibits fungal cell membrane synthesis, targeting Malassezia species.

Question 65

What is a potential side effect of selenium sulfide shampoo?

Answer 65

Selenium sulfide can cause skin irritation and dryness if overused.

Question 66

Why are topical calcineurin inhibitors preferred in certain regions?

Answer 66

They are recommended for regions susceptible to telangiectasia and skin atrophy caused by corticosteroids.

Question 67

What are the recommended management options for Infantile Seborrheic Dermatitis?

Answer 67

Options include using superabsorbent disposable diapers, cleaning with soap and alcohol-free compounds, applying topical antifungal treatments, and using mild-potency topical steroids.

Question 68

How does Infantile Seborrheic Dermatitis differ from Atopic Dermatitis?

Answer 68

ISD is self-limited, primarily affects the vertex scalp, and presents with greasy scales, while atopic dermatitis is intensely pruritic and primarily affects the face.

Question 69

What evidence supports the use of tea tree oil in seborrheic dermatitis?

Answer 69

Tea tree oil has antifungal properties against Malassezia furfur and improves severity, pruritus, and greasiness.

Question 70

What is the nature of seborrheic dermatitis?

Answer 70

Self-limited, regresses spontaneously ## Footnote Severity decreases with age.

Question 71

What are the lesion characteristics of seborrheic dermatitis?

Answer 71

Adherent, yellow-brown, greasy scale ## Footnote Intensely pruritic, erythematous papules with excoriation, vesicles, and serous exudate.

Question 72

What evidence supports the use of tea tree oil for seborrheic dermatitis?

Answer 72

Tea tree oil has antifungal properties, particularly against Malassezia furfur, and has been shown to improve severity, pruritus, and greasiness in seborrheic dermatitis.

Question 73

Why is 1% hydrocortisone preferred over higher-potency steroids for infants with seborrheic dermatitis?

Answer 73

Mild-potency steroids like 1% hydrocortisone are preferred to minimize the risk of side effects in infants.

Question 74

Why should patients with seborrheic dermatitis avoid alcohol-based cleaning agents?

Answer 74

Alcohol-based agents can irritate the skin and exacerbate seborrheic dermatitis.