Infant Seborrhoeic Dermatitis

Synonyms: Cradle Cap, Vernix Caseosa

Seborrhoeic dermatitis is a condition that tends to affect adults. It often starts around puberty and peaks around 40. However, it can affect infants and when it causes hard scales on the scalp this is often referred to as cradle cap.

Seborrhoeic dermatitis is a papulosquamous disorder affecting the areas with most sebum such as the scalp, face, and trunk. An association with a yeast infection has been known for over 30 years. Seborrhoeic dermatitis is associated with normal levels of Malassezia but an abnormal immune response. Immunological abnormalities, and activation of complement are involved. Malassezia has lipase activity that may be important in releasing inflammatory free fatty acids. There is also an ability to activate the alternative complement pathway.

Malassezia furfur appears to be the species associated with infantile seborrhoeic dermatitis.¹

The literature can be confusing in that sometimes, especially in older papers, it mentions Pityrosporum ovale whilst other times it mentions Malassezia furfur. It seems that Pityrosporum ovale and Pityrosporum orbiculare are now classified as Malassezia furfur.

Seborrhoeic dermatitis is extremely common in infants. Many children with the condition are not brought to the attention of the medical services and so the precise incidence is unknown.

Seborrhoeic dermatitis presenting in infancy is a very common condition which may be brought to the attention of the health visitor or GP. In the majority of cases it is a benign self limiting condition which usually clears spontaneously during the first 12-24 months of life, but in a small number it can be particularly troublesome and require treatment. Seborrhoeic dermatitis occurs most commonly in the lipid-rich areas of skin, and in infants occurs predominantly on the scalp and upper face producing an appearance which may give rise to some concern from parents.

Cradle cap is very common and usually appears in the first few weeks of life. The association with fungal infection does not seem so clear. There are greasy, yellow scaling patches that may eventually coalesce to a thick, scaly layer. The condition is not itchy and the child is not distressed by it.
Seborrhoeic dermatitis in infants presents as areas of flaky patches of skin or plaques, which appear almost greasy or waxy in appearance, other findings may include:

• Plaques around ears, nose and eyebrows
• Sharply demarcated brightly erythematous rash in groin and perianal area (may be confused with ammoniacal dermatitis or candidiasis)
• Itching
• Excoriation of the skin where the child has scratched.
• "Dandruff"
• Loss of small amounts of hair in the area of the plaques
• Patches of redness surrounding the plaques
• Areas of secondary bacterial infection where scratching has occurred.

• Areas of reddened skin with scales may be mistaken for eczema.
• If the plaques become infected, they may resemble impetigo.
• Psoriasis may cause confusion and can look similar in babies
• Fungal infections with tinea

Usually no investigation is required and the diagnosis is made on clinical appearance alone. Seborrhoeic dermatitis is uncommon in preadolescent children, and tinea capitis is uncommon after adolescence. Dandruff in a child is more likely to represent a fungal infection. A fungal culture may aid the diagnosis but the disease may occur with a negative culture and a positive culture is not diagnostic.

Non-Drug

Seborrhoeic dermatitis in infancy is a benign, self limiting condition and often the most appropriate management is reassurance for the parents that the condition is not serious and will disappear on its own in good time. The parents may be advised that gently brushing the child's hair, or massaging the scalp with baby oil on a regular basis may help to loosen the plaques.

Drugs

Although little research has focused specifically on the treatment of seborrhoeic dermatitis in infants, the condition in adults is very similar, and the treatment used in infants is based on this research.² In adults, both topical steroids and topical antifungal agents such as ketoconazole are used with good effect,³ either as shampoo, cream or lotion, and although the incidence of side effects with both agents is very low, anti-fungal agents appeared to be slightly better tolerated and appeared to be better at preventing recurrences. Steroid creams, if used, should be kept mild and short term.⁴ The safety of using anti-fungal agents in infants has been assessed using ketoconazole twice a week for 4 weeks, and using this regime, no detectable level of ketoconazole was found in the serum after 4 weeks and there was no change in the liver function test results.⁵

Do not over-treat because of anxious parents. Treat the child, not the parents.

Secondary infection can occur, particularly if the lesions are itchy and the child scratches.

The majority of children with seborrhoeic dermatitis will show resolution and have no further skin disease. There is an increased risk of adult seborrhoeic dermatitis developing but this probably affects less than 10%⁶ and other skin diseases do not seem to be at increased risk.