Seborrhoeic Dermatitis

Common in hair-bearing areas of the body, esp. the scalp and eyebrows. It can also affect the face, neck, axillae and groins, eyelids (blepharitis), external auditory meatus and nasolabial folds. The presternal area is often involved. In infancy, known as ‘cradle cap’ if it affects the scalp, or nappy rash/diaper dermatitis if it involves the napkin area. It is likely caused by a reaction to the yeast Malassezia sp. Itching is minimal (cf. atopic dermatitis).

Principles of treatment

• Keratolytics (e.g. salicylic acid) are used to lift the scale

• Anti-yeast treatments reduce the skin’s load of Malassezia sp., e.g. ketoconazole, miconazole, ciclopirox

• Topical corticosteroids target inflammation and pruritus, although itch (if present) is usually mild

Medication: children

Scalp: (Note: May resolve spontaneously within a few months)

• 1–2% sulphur and 1–2% salicylic acid in aqueous cream or same cream with 2% liquor picis carbonis (LPC) or

• Egozite cradle cap lotion (6% salicyclic acid)

• apply overnight to scalp, wash off next day with soap substitute

• use daily or 2nd daily until clears

• if persistent, use desonide 0.5% lotion, daily after bath

• if thick scale, add coal tar (LPC) 3–6% + salicylic acid 3% in aquaeous cream, up to twice wkly

Face, flexures and trunk:

• desonide 0.05% lotion or hydrocortisone 1% ointment, bd for up to 7 d

Napkin area:

• mix equal parts 1% hydrocortisone with nystatin or miconazole + zinc oxide

Medication: adults

Scalp:

• ketoconazole shampoo twice-weekly to daily

• if inadequate, add betamethasone dipropionate 0.05% lotion for 7 nights

Face and body:

• wash regularly with bland soap

• hydrocortisone 1% + clotrimazole 1% d–bd, up to 2 wks or

• if inadequate response, use methylprednisolone aceponate 0.1% cream daily in combination with ketoconazole 2% or bifonazole 2% creams daily for up to 2 wks