Seborrheic Dermatitis

Background

1. Definition
   • Patchy, greasy, scaly and crusty skin rash that mainly occurs on the scalp of neonates (View image)
     • Confined to the scalp
2. Synopsis
   • Possibly due to
     • Overactive sebaceous glands
     • Due to the mother's hormones
     • There may be a relationship with skin yeasts (malassezia)
   • Treatment of cradle cap
     • Mild baby shampoos
     • Regular shampooing and soft brushing should help to remove the scales

Pathophysiology

1. Etiology/Risk Factors
   • Drugs
     • Li, Gold
     • IFN-alpha, Cimetidine, Griseofulvin, phenothiazines, psoralen
   • HIV
   • Parkinson
   • DM
   • Epilepsy
   • Malabsorption disease
2. Pathology
   • Chronic inflammatory disorder of skin (usually high sebum areas)
   • Possibly abnl response to Pityrosporum ovale (Malassezia fungus)
     • P. ovale lipase leads to inflammatory free fatty acids
     • Activates alternate complement pathway
     • T Cell, phytohemagglutinin, concanavalin response
     • Depressed antibody response versus controls
   • Humidity, stress, trauma, seasonal: exacerbating factors
   • Avoidance of hair washing increases scale formation, inflammation
3. Epidemiology
   • Morbidity/Mortality
     • Disease persists into adulthood, waxes/wanes
   • Incidence/Prevalence
     • Most common:
       • Infants < 3 mo
       • Adults 30-60 yo
     • Eruptions:
       • Winter-early spring

Diagnostics

1. History/Symptoms
   • Mainly a clinical diagnosis
   • Scaling, flaking skin
   • Dry scalp
   • Pruritis
     • Less common than in atopic dermatitis
   • Waxing/waning course
2. Physical Exam/Signs
   • Lesions:
     • Sharply demarcated
     • More intense color at periphery
     • Clearing at center
     • Color: pink-yellow to red-brown
     • Vesicles and crusting may occur due to irritation (rare)
     Scalp:
     • Patchy scaling leads to thick crusts (like Psoriasis)
     • Dry, flaky desquamation: "dandruff"
     • Infants: greasy, adherent scale at vertex
   • Skin: greasy scale over inflamed, erythematous skin
     • Hair-bearing, oily areas of skin (eyebrows, scalp, nasolabial folds)
     • Also: inguinal/inframammary folds, axilla, perineum
   • Hypopigmentation seen in African Americans
   • Secondary infection possible (especially intertriginous creases, eyelids)
     • Infants may have Candidal overgrowth
     • Oozing, crusting
   • Generalized disease in immunocompromised, CHF, Parkinson, premature infants
     • Severe facial eruption (SLE-like) in AIDS (25-50% of patients)
3. Labs/Tests
   • Fungal culture: rule out Tinea Capitis if indicated
4. Differential Diagnosis
   • Atopic dermatitis
   • Irritant contact dermatitis
   • Allergic contact dermatitis
   • Asteatotic eczema
   • Tinea capitis
   • Tinea corporis
   • Drug eruptions
   • Impetigo
   • Pityriasis rosea

Treatment

1. Initial/Prep/Goals
   • Educate patient on proper hygiene
     • Skin care (emollients)
     • Bathing
     • Scalp: frequent shampooing
   • Avoid manually removing the scales
2. Medical/Pharmaceutical
   • Shampoos with selenium, salicylic acid, tar or sulfur
     • Use every day or every other day
   • Topical antifungals
     • Ketoconazole
       • Low potency
       • Used initially to reduce inflammation
       • Indicated for more severe or persistent cases
       • Appears to be safe and efficacious
   • Topical corticosteroids
     • Fluocinolone
       • For acute outbreaks only
   • Mineral oils, glycerol then dishwashing detergents for thick scales
   • Other areas
     • Class 4 Topical corticosteroids
       • Hydrocortisone for acute outbreaks only
     • PO Corticosteroids for severe, unresponsive disease
     • Topical antifungals creams

Disposition

1. Usually outpatient/home care
2. Further Management
   • Diagnostic testing
     • Skin biopsy: if Dx in doubt (Psoriasis, Tinea Capitis)
     • HIV, immune compromise testing: if indicated
3. Discharge/Follow-up instructions
   • Follow up with Primary Care Physician as appropriate
     • Change medications if presumed causative
   • Prevention
     • Frequent salicylic acid/sulfur shampooing may prevent recurrences
     • Do not skip hair washing because scalp "feels dry"

References

1. Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 5th ed. Philadelphia, Pa.: Elsevier Mosby; 2009;Chapter 8
2. Stefanaki I, Katsambas A. Therapeutic update on seborrheic dermatitis. Skin Therapy Lett. May 2010;15(5):1-4
3. Danby FW, Maddin WS, Margesson LJ, Rosenthal D. A randomized, double-blind, placebo-controlled trial of ketoconazole 2% shampoo versus selenium sulfide 2.5% shampoo in the treatment of moderate to severe dandruff. J Am Acad Dermatol 1993;29:1008
4. Johnson BA, Nunley JR. Treatment of Seborrheic Dermatitis. Am Fam Physician, May 1, 2000;61(9):2703-2710
5. Rudikoff D, Cohen S, Scheinfeld N. Atopic Dermatitis and Eczematous Disorders, 1st ed., CRC Press, 2014;Chapter 18
6. Bolognia JL, Jorizzo JL, Schaffer JV. Dermatology, 3rd ed., Elsevier Health Sciences, 2012;Chapter 13

Contributor(s)

1. Ballarin, Daniel, MD

Updated/Reviewed: July 2020