Seborrhoeic Dermatitis in the Adult

Essentials

• Diagnosis is based on the typical appearance and location of the rash.
• Seborrhoeic dermatitis has different clinical manifestations.
• Management consists of symptomatic treatment.

Epidemiology and aetiology

• Prevalence about 3-5%
• Endogenous and multifactorial
• Increased sebum production (seborrhoea), the properties of sebum and the patient's immunological response favour the growth of Malassezia yeasts and other microbes. Malassezia yeasts degrade sebum to fatty acids, which results in skin irritation.
• There have been reports of an association between sudden onset or flare ups and certain conditions (e.g. immunosuppression, HIV infection, Parkinson's disease) and medicines (lithium, haloperidol, antiepileptic drugs, systemic glucocorticoids).

Symptoms and signs

• Well-demarcated, scaly and erythematous patchy lesions that may coalesce to form larger lesions on the face and other areas
• Intermittent symptom emergence on sebum-rich skin areas.
  • Scalp (pictures 1 2)
  • Face (picture 3), eyebrows, nasolabial folds (picture 4), "sideburn" areas (pictures 5 6)
  • Pinna of the ear and ear canal
  • Central upper parts of the chest and, sometimes, of the back (high sweat rate areas: the bra triangle and the triangular area between the shoulders and the scapulae, picture 7)
  • Armpits (picture 8)
  • Gluteal cleft (picture 9), groins (pictures 10 11), genital area (glans penis, scrotum; picture 12)
• Various clinical manifestations include
  • greasy or dry scaling of the scalp, sometimes thick scalp plaques (picture 13)
  • seborrhoeic dermatitis of the ear canal and ears
  • eyelid dermatitis, seborrhoeic blepharitis
  • patchy lesions on the high sweat rate areas of the upper torso
  • well-demarcated erythema and excoriation in the flexural areas (= an intertrigo)
  • seborrhoeic dermatitis of the gland penis (balanitis) or testicles.

Diagnosis

• Diagnosis is based on the typical appearance and location of the rash.
• In some cases fungal samples (for microscopy and culture) are indicated to exclude tinea. Malassezia yeasts can be seen in microscopy, no growth in the fungal culture.

Differential diagnosis

• Psoriasis Psoriasis: the scales are thicker, the sites of predilection are different, i.e. elbows and knees, palms and soles. Nail changes, and psoriasis often has a familial occurrence.
• Atopic dermatitis: different typical locations
  • The scalp lesions are sometimes identical with those caused by seborrhoeic dermatitis
• Tinea: must be borne in mind, for example in dermatitis of the groins
• Tinea versicolor: on the trunk

Treatment

• No permanent results are usually achieved with treatment, which is symptomatic and needs to be repeated from time to time (a course lasting for 1-2 weeks) when symptoms worsen.
• Maintenance therapy, perhaps once or twice weekly, should be continued in order to reduce the frequency of exacerbations .
• Reduction of dandruff and sebo-suppression
  • Seborrhoeic areas should be washed more often than normally (daily).
  • Basic topical ointments in gel form (e.g. products containing propylene glycol) to wash with, or basic topical ointments may be applied after washing.
• Face and body
  • Topical mild to moderately potent glucocorticoid creams Topical Anti-Inflammatory Agents for Seborrhoeic Dermatitis of the Face or Scalp
  • Creams containing a combination of a glucocorticoid and an azole antifungal
  • Glucocorticoid creams are used periodically, e.g. during periods of exacerbation once or twice daily in courses of 1-2 weeks.
  • Tacrolimus ointment or pimecrolimus cream as a periodical therapy 1-2 times daily for a period of 3-4 weeks or as maintenance therapy eg. once or twice a week
  • Creams, gels or shampoos containing topical antifungals Topical Antifungals for Seborrhoeic Dermatitis (ketoconazole, clotrimazole, miconazole, tioconazole) or terbinafine ointment .
  • Antifungals may be used in acute exacerbations once or twice daily for 1-2 weeks, and they are suitable for prophylactic maintenance therapy once or twice a week.
  • Metronidazole or azelaic acid either as gel or cream in courses of 3-4 weeks and, if needed, as maintenance therapy 1-2 times a week..
• Scalp
  • Scalp plaques can be softened with 3-5% salicylic acid ointment in the evenings and washed away in the mornings.
  • Scalp may be washed with ketoconazole shampoo or seleniumsulphide shampoo
  • Glucocorticoid solutions (equivalent doses) to the scalp (Class I-III) Topical Anti-Inflammatory Agents for Seborrhoeic Dermatitis of the Face or Scalp
  • In treatment-resistant cases, a sequential treatment schedule using a glucocorticoid shampoo in courses of 3-4 weeks may be tried.
• Ears and ear canals
  • Mild to moderately potent glucocorticoid ointments or solutions 1-2 times daily in courses of 1-2 weeks
• Flexural areas
  • Mild to moderately potent glucocorticoid ointments
  • A combination ointment of a glucocorticoid and an azole group antifungal
  • Tacrolimus ointment or pimecrolimus cream periodically 1-2 times daily in courses of 3-4 weeks, or as maintenance therapy, e.g. 1-2 times a week.
  • The effect of the warm and moist environment can be reduced by application of talc or azole-containing powder after wash in the mornings and zinc paste after wash in the evenings.
• Severe and treatment-resistant cases
  • A course of an oral antifungal drug may be combined with topical therapy, itraconazole 200 mg once daily for 7 days, for example. Interactions with other medications must be checked.
  • Also oral fluconazole or terbinafine has been used as courses.

Consultation

• In severe cases and cases refractory to therapy a dermatologist should be consulted.

References

• Borda LJ, Perper M, Keri JE. Borda LJ, Perper M, Keri JE. Treatment of seborrheic dermatitis: a comprehensive review. J Dermatolog Treat 2019;30(2):158-169. . J Dermatolog Treat. 2018 May 24:1-12.ketoconazole shampoo 2%: a randomized, controlled study. Br J Dermatol 2011;165(1):171-6. [PubMed]
• Cicek D, Kandi B, Bakar S et al. Pimecrolimus 1% cream, methylprednisolone aceponate 0.1% cream and metronidazole 0.75% gel in the treatment of seborrhoeic dermatitis: a randomized clinical study. J Dermatolog Treat 2009;20(6):344-9. [PubMed]
• Warshaw EM, Wohlhuter RJ, Liu A ym. 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):257-64. [PubMed]
• Seckin D, Gurbuz O, Akin O. Metronidazole 0.75% gel vs. ketoconazole 2% cream in the treatment of facial seborrheic dermatitis: a randomized, double-blind study. J Eur Acad Dermatol Venereol 2007;21(3):345-50. [PubMed]