Definition
A.A common chronic, erythematous, scaling dermatosis, seborrheic dermatitis occurs in areas of the most active sebaceous glands, such as the face and scalp, body folds, and presternal region.
Incidence
A.Seborrheic dermatitis is very common, affecting approximately 1% to 5% of the general population.
B.Incidence is higher in HIV-infected individuals, ranging from 34% to 83%.
Pathogenesis
A.Etiology is unknown. There is a possibility that it is hormonally dependent, has a fungal (Pityrosporum ovale or Candida albicans) component, is neurogenic, or may reflect a nutritional deficiency.
B.Currently, it is identified as an inflammatory disorder that most probably results from a dysfunction of sebaceous glands.
Predisposing Factors
A.Possible link between infantile and adult forms.
B.Possible familial trend.
C.High association with HIV-infected individuals.
Common Complaints
A.Dandruff,
dry flaky scalp.
B.Rash with sticky flakes.
Often no presenting complaints are found on a routine physical exam.
Other Signs and Symptoms
A.Variable pruritus, often increased with perspiration and winter.
B.Oily, flaking skin on erythemic base around ears, nose, eyebrows, and eyelids.
C.Red, cracking skin in body folds, axilla, groin, or anogenital, submammary, or umbilical areas.
D.Primary lesions: Plaques.
E.Secondary lesions: Erythema, scales, fissures, exudate, and symmetric eyelid involvement.
F.Lesions with drainage or crusting may indicate secondary bacterial infection.
G.Distribution area in adults: Scalp, eyebrows, paranasal area, nasolabial fold, chin, behind ears, chest, and groin.
Subjective Data
A.Identify location, onset, and progression of symptoms.
B.Ask the patient to describe symptoms. Ask if the skin is itchy or painful.
C.Assess lesions for any associated discharge (blood or pus).
D.Elicit information regarding use of topical medications, soaps, creams, or lotions. Quiz patient regarding any oral medications being taken.
E.Determine whether there were any preceding systemic symptoms (fever, sore throat, anorexia, or vaginal discharge).
F.Rule out any possible exposure to industrial or domestic toxins.
G.Ask the patient to identify what improves or worsens this condition.
Physical Examination
A.Inspect:
1.Inspect skin; note areas of lesions and distribution.
2.Assess eyes for blepharitis.
3.Inspect ears and nose.
B.Palpate: Palpate skin, noting texture and moisture.
Diagnostic Tests
A.None required.
B.May consider possible skin biopsy to rule out other conditions if suspicious.
Differential Diagnoses
A.Seborrheic dermatitis.
B.Atopic dermatitis.
C.Candidiasis.
D.Dermatophytosis.
E.Histiocytosis X.
F.Psoriasis vulgaris.
G.Rosacea.
H.Systemic lupus erythematosus.
I.Tinea capitis.
J.Tinea versicolor.
K.Vitamin deficiency.
L.Impetigo.
M.Eczema.
N.Secondary syphilis.
Plan
A.General interventions.
B.Shampooing is the foundation of treatment:
1.Use medicated shampoos as directed (Selsun Blue, Exsel, or Nizoral).
2.Shampoo daily with baby shampoo using a soft brush.
3.If scalp does not clear after 1 to 2 weeks of treatment, it is appropriate to use ketoconazole 2% cream.
4.Seborrheic blepharitis:
a.Hot compresses plus gentle debridement with cotton-tipped applicator and baby shampoo twice a day.
b.For secondary bacterial infection, sulfacetamide sodium 10% (ophthalmic Sodium Sulamyd).
5.Continue treatment for several days after lesions disappear.
C. 
See Section III: Patient Teaching Guide Seborrheic Dermatitis.
D.Pharmaceutical therapy:
1.Most shampoos should be used two times per week. Those with coal tar can be used three times per week.
2.Medicated shampoos:
a.Coal tar (Denorex, T/Gel, Pentrax, Tegrin) shampoo; apply as directed.
b.Salicylic acid (Ionil Plus, P and S) shampoo; apply as directed.
c.Selenium sulfide (Exsel, Selsun Blue); shampoo daily.
d.Ketoconazole 2% (Nizoral) cream; apply to affected area twice daily for 4 to 6 weeks.
e.Combination shampoos: Coal tar and salicylic acid (T/Sal); salicylic acid and sulfur (Sebulex). These shampoos may be used one to two times a week, alternating with other shampoos during the week. Always apply corticosteroids as thin layer only; avoid eyes.
3.Topical corticosteroid lotions or solutions: Use in combination with medicated shampoo if 2 to 3 weeks of treatment with shampoo alone fails.
4.Adults: Scalp:
a.Start with medium potency, for example, betamethasone valerate 0.1% lotion 20 to 60 mL twice daily.
b.If treatment is not effective in 2 weeks, increase potency, for example, fluocinonide 0.05%
solution 20 to 60 mL twice daily, or fluocinolone acetonide 0.01% oil 120 mL nightly with shower cap.
c.As dermatitis is controlled, decrease to mild potency, for example, hydrocortisone 1% to 2.5% lotion 60 to 20 mL once or twice daily.
5.Adults: Face or groin:
a.Low-potency agents, for example, hydrocortisone 1% cream or desonide 0.05% cream once or twice daily.
b.Consider lotion for eyebrows for easier application.
c.Metronidazole 1% gel on face once or twice daily.
6.Recalcitrant disease:
a.Add ketoconazole 2% cream (15, 30, or 60 g) every day.
b.Sulfacetamide sodium 10%, with sulfur 5%, lotion 25 g once or twice daily
Follow-Up
A.Advise the patient to call the office in 5 to 6 days to report progress.
B.The patient should return to the office if no improvement is seen.
Consultation/Referral
A.Refer the patient to a dermatologist if the condition does not clear in 10 to 14 days.
Individual Considerations
A.Pregnancy: Ketoconazole is not recommended.
B.Geriatrics: Seborrheic dermatitis is one of the most common inflammatory skin disorders with the elderly population. Patients with light dry skin have the greater risk of an occurrence, especially during the winter.