What Is Causing This Infant’s Yellow, Scaly Rash and Peeling Skin?
A mother brought in her previously health 5-month-old infant for evaluation of a rash on his head, face, neck, and trunk, including the genital area. She reported that the boy’s skin initially had developed some redness on and off for a few weeks. Over the last 3 to 4 days, however, the affected skin had begun to peel. She reported no fever or irritability, and that the boy had been eating fine, with normal wet diapers and normal stools. The infant had no symptoms of upper respiratory infection, and he had no sick contact or history of travel.
On physical examination, the infant was vigorous, was in no acute distress, and was well hydrated. He had patches of yellow, greasy scales over his scalp and umbilical area, in addition to erythema and peeling of skin in the creases behind his ears and on his neck, upper chest, back, and genital area. There was no tenderness, increased warmth, or swelling, and no drainage from the lesions.
What explains this infant’s dermatologic symptoms?
A. Tinea corporis
B. Seborrheic dermatitis
C. Psoriasis
D. Eczema
(Answer and discussion on next page)
Answer: B, seborrheic dermatitis
Seborrheic dermatitis is a chronic, relapsing, inflammatory condition that can affect infants and adults alike. Like many other skin conditions, seborrheic dermatitis tends to worsen in the cold and dry winter months and improve during the summer months. Although its cause is not completely understood, it has a predilection for areas that are abundant in sebaceous glands, including the face, scalp, chest, and anogenital region.
It is unknown whether the causes of seborrheic dermatitis are the same in infants and older persons.1 The lipid-dependent fungi of the genus Malassezia (particularly M ovalis, formerly known as Pityrosporum ovale) has been indirectly associated with the development of seborrheic dermatitis. Malassezia are ubiquitous on the skin, and the fungi’s lipophilic nature could explain the condition’s tendency to develop in areas rich in sebaceous glands.2 Further supporting the role of Malassezia, the condition improves with exposure to sunlight, because UVA and UVB radiation inhibit M ovalis growth.3
In susceptible persons, the inflammatory process may be mediated by fungal metabolites released from sebaceous triglycerides. The lipid layer of Malassezia fungi also can modulate proinflammatory cytokine production by keratinocytes.4 Seborrheic dermatitis also tends to be more severe in immunocompromised individuals (eg, with HIV/AIDS). Still, while antifungal agents are effective treatment for seborrheic dermatitis, no evidence supports the direct role of Malassezia in the condition.
Poorly defined, erythematous, scaling plaques characterize seborrheic dermatitis. The rash can involve one area or it can spread diffusely.1 It is commonly known as cradle cap, because scaling usually is present on the scalp. Other affected areas can include the face, ears, and neck. Erythema often is seen in the flexural folds and intertriginous areas.
The diagnosis is based on a detailed history and thorough physical examination. Biopsy usually is not indicated unless the diagnosis is uncertain. The differential diagnosis of seborrheic dermatitis includes psoriasis, rosacea, atopic dermatitis, tinea corporis, and rarer conditions such as secondary syphilis, systemic lupus erythematosus, candidiasis, and dermatomyositis.
Seborrheic dermatitis during infancy usually is self-limited, resolving within a few weeks to several months. The acute phase of may be treated effectively with topical antifungals, corticosteroids, and/or other agents with nonspecific antimicrobial or anti-inflammatory properties. The intermittent use of topical antifungals helps prevent recurrence. 
For cases involving the scalp, antifungal shampoos containing selenium sulfide 2.5%, ketoconazole 2%, or ciclopirox 1% have been shown to be effective.5 Seborrheic dermatitis involving other parts of the body can be effectively managed with topical corticosteroid creams, topical antifungal agents, or a combination of the two. Care should be taken to avoid using high-potency corticosteroids on the face and intertriginous areas due to the possible adverse effect of skin atrophy.
Calcineurin inhibitors (ie, tacrolimus and pimecrolimus) act as anti-inflammatory agents by preventing T cell activation and are used in the treatment of facial seborrheic dermatitis. Calcineurin inhibitors have been shown to be as effective against seborrheic dermatitis as hydrocortisone and ketoconazole.6 Lithium salts (ie, lithium succinate and lithium gluconate) have been shown to be effective in areas other than the scalp, although the mechanism is poorly understood.7 Oral antifungals may be considered for severe or refractory cases.
Sharda Udassi, MD, is an associate professor in the Division of General Academic Pediatrics at the University of Florida College of Medicine in Gainesville.
Laura Schoeneberg, MD, is a first-year pediatric resident at the University of Florida College of Medicine.
Jessica Joseph is a medical student at the University of Florida College of Medicine.
Sanjeev Y. Tuli, MD, is a professor of pediatrics, associate chair for Clinical Affairs and Community Relations, and Chief of the Division of General Academic Pediatrics at the University of Florida College of Medicine.
References
1. Morelli JG. Seborrheic dermatitis. In: Kliegman RM, Stanton BF, St. Geme JW III, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:2253-2254.
2. DeAngelis YM, Gemmer CM, Kaczvinsky JR, Kenneally DC, Schwartz JR, Dawson TL Jr. Three etiologic facets of dandruff and seborrheic dermatitis: Malassezia fungi, sebaceous lipids, and individual sensitivity. J Investig Dermatol Symp Proc. 2005;10(3):295-297.
3. Johnson BA, Nunley JR. Treatment of seborrheic dermatitis. Am Fam Physician. 2000;61(9):2703-2714.
4. Thomas DS, Ingham E, Bojar RA, Holland KT. In vitro modulation of human keratinocyte pro- and anti-inflammatory cytokine production by the capsule of Malassezia species. FEMS Immunol Med Microbiol. 2008;54(2):203-214.
5. 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(6):1008-1012.
6. Warshaw EM, Wohlhuter RJ, Liu A, et al. Results of a randomized, double-blind, vehicle-controlled efficacy trial of pimecrolimus cream 1% for the treatment of moderate to severe facial seborrheic dermatitis. J Am Acad Dermatol. 2007;57(2):257-264.
7. Efalith Multicenter Trial Group. A double-blind, placebo-controlled, multicenter trial of lithium succinate ointment in the treatment of seborrheic dermatitis. J Am Acad Dermatol. 1992;26(3):452-457.