Seborrhoeic dermatitis (syn. seborrhoeic eczema)

Latest update 17/09/2010

This chapter is set out as follows:

• Aetiology
• Key diagnostic features
• Management of skin symptoms
• Management of ocular symptoms

Aetiology

• Appears to be caused by the yeast Malassezia ovale (M. ovale), formely known as pityrosporum ovale
• It is unclear as to how M. ovale induces inflammation and scaling, although there is a hypothesis that the yeast hydrolyzes sebum and releases a mixture of saturated and unsaturated fatty acids. The fatty acids are taken up by the yeast but the unsaturated fatty acids breach the skin's barrier function causing the inflammatory reaction
• It is more common and can be much more severe in patients with HIV and in Parkinson's disease

Key diagnostic features

• Peak age is 18-40 but it can occur at any age. It is more common in males
• Appearance - red, sharply marginated lesions / patches covered with greasy-looking yellowish scales
• Distribution – affects areas with a rich supply of sebaceous glands:
  • Scalp and behind the ears. More extensive involvement of the ears with otitis externa may occur
  • Face – medical eyebrows (can be associated with chronic blepharitis), glabella and nasolabial folds
  • Upper trunk - presternal and interscapular regions
  • Flexures – axillae, groins, umbilicus, anogenital and submammary regions. Areas under spectacles or hearing aids may also be involved
• Seborrhoeic dermatitis or psoriasis? There are some occasions when it can be difficult to distinguish between seborrheoic dermatitis and psoriasis:
  • Face - even after general examination of the skin it can be difficult to differentiate facial psoriasis from seborrhoeic dermatitis. Such patients are sometimes termed as have 'sebo-psoriasis'
  • Infants – some infants develop erythema and scaling in the first 6 months of life. It often begins in the napkin area but may also occur on the scalp (cradle cap) and extend to other flexures such as the neck creases and the axillae. Unlike with dermatitis patients are not unduly distressed. Opinion is split as to whether this actually represents psoriasis as opposed to seborrhoeic dermatitis. For more information please refer to the chapters on psoriasis and eczema (napkin dermatitis)

Management of skin symptoms

• Provide a patient information leaflet

• Scalp:
  • Nizoral ® (ketoconazole 2%) shampoo. Initially use 2-4 times a week then once every 2 weeks for maintenance. An alternative is Selsun ® shampoo (selenium sulphide)
  • For itch and erythema - a topical steroid scalp application or mousse
  • For scale and crusts - olive oil for mild crusting. Sebco ® ointment massaged in and left on for 2-4 hours can be very useful for thicker scale / crust
• Topical treatments:
  • Topical Nizoral ® cream - some patients find this causes too much skin irritation, in which case they can use either Canestan ® or Daktarin ® cream
  • Topical steroids such as eumovate can be added in for flare-ups but should only be used for 1-2 days at a time on facial skin
  • Try to avoid giving patients combination products such as Daktacort ® or Trimovate ® for use on the face as they may lead to over usage of topical steroids
  • If there are concerns about overuse of steroids consider the off-label use of topical calcineurin inhibitors e.g. Elidel ® cream (Pimecrolimus) or Proptopic ® ointment (Tacrolimus)
• More extensive disease
  • Systemic Sporanox ® (itraconazole) 100mg per day for 14-21 days
  • If symptoms relapse frequently consider 8-week courses of systemic tetracyclines (they have an anti-inflammatory effect on the skin)
  • Consider HIV in patients with more severe symptoms
• Referral to secondary care – for patients who fail to respond to the treatments referred to above. In such cases a prolonged course of low dose isotretinoin, used off-label, may be considered

Management of ocular symptoms

• Lid hygiene: clean eyelids using cotton wool soaked in cooled boiled water
• Artificial tears: should be applied liberally through the day if the eyes are dry / sore. If necessary a lubricating ointment, sometimes containing an antibiotic preparation may be used at night
• As with rosacea, systemic tetracyclines can be useful for more troublesome symptoms such as blepharitis. Erythromycin can be used in patients unable to take tetracyclines. Patients need to take 6-8 week courses

	Figure 1 – Seborrhoeic dermatitis Erythema of the central face and scaling of the nasal ala
	Figure 2 – Seborrhoeic dermatitis Erythema and fine scaling (copied with kind permission from Dermatoweb)
	Figure 3 - Seborrheoic dermatitis Central face
	Figure 4 – Same patient as figure 3
	Figure 5 – Seborrhoeic dermatitis Scaling very evident (copied with kind permission from Dermatoweb)
	Figure 6 – Seborrhoeic dermatitis Involvement of eyebrows with fine scale. Eyelids also involved
	Figure 7 – Seborrhoeic dermatitis of the scalp Fine scaling and ill-defined erythema (copied with kind permission from Dermatoweb)
	Figure 8 – Seborrhoeic dermatitis (copied with kind permission from Dermatoweb)
	Figure 9 - Seborrhoeic dermatitis (copied with kind permission from Dermatoweb)
	Figure 10 –Seborrhoeic dermatitis in darker skin Distribution similar with eyebrows and scalp affected (copied with kind permission from Dermatoweb)
	Figure 11 –Seborrhoeic dermatitis Can cause quite bizzare patterns on the trunk. With an odd shaped rash the differenential diagnosis may include lupus. Patient responded well to treatment
	Figure 12 – Same patient as figure 11
	Figure 13 –Seborrhoeic dermatitis of the chest Lesions sharply marginated
	Figure 14 - Seborrhoeic dermatitis
	Figure 15 – Seborrhoeic dermatitis around the scrotum. Other areas also involved
	Figure 16 – Extensive seborrhoeic dermatitis
	Figure 17 – Same patient as figure 16 Sharply marginated
	Figure 18 – Seborrhoeic dermatitis with blepharitis Erythema and fine scaling
	Fig 19 – Seborrhoeic dermatitis or psoriasis?