Discoid dermatitis

Discoid dermatitis (also known as discoid eczema or nummular eczema) presents as round or oval plaques with clearly demarcated edges. Unlike tinea (ie ringworm) of the body, these plaques do not have central clearing. See here for photos of discoid dermatitis. The plaques are intensely itchy and prone to bacterial infection after excoriation from repeated scratching. The condition usually presents in middle to late adulthood, but can occur in children. The cause is unknown.

Figure 1. Discoid dermatitis

Note: Photo sourced with permission from Dr Michelle McRae.

Note: Photo sourced with permission from Dr Michelle McRae.

For discoid dermatitis, apply a potent topical corticosteroid. An ointment is preferred to a cream because it has better skin plaque penetration, and stings less. Use:

1betamethasone dipropionate 0.05% ointment topically, once to twice daily for 2 weeks betamethasone dipropionate betamethasone dipropionate betamethasone dipropionate

OR

1betamethasone valerate 0.1% ointment topically, once to twice daily for 2 weeks betamethasone valerate betamethasone valerate betamethasone valerate

OR

1mometasone furoate 0.1% ointment topically, once daily for 2 weeks. mometasone furoate mometasone furoate mometasone furoate

If the skin is not clear after 2 weeks, use a more potent topical corticosteroid with a modified dressing. If discoid dermatitis is localised, use an occlusive dressing. If discoid dermatitis is widespread, use a wet dressing or the ‘soak and smear’ technique. Use:

betamethasone dipropionate 0.05% ointment in optimised vehicle topically, once daily until skin is clear or for up to 4 weeks. betamethasone dipropionate betamethasone dipropionate betamethasone dipropionate

If the skin does not respond to a more potent topical corticosteroid with modified dressing, refer for dermatologist advice. See also Lack of response to treatment of dermatitis.

If skin plaques are moist or crusted, take a bacterial swab for cultures and susceptibility testing. If skin is infected, treat as for infected atopic dermatitis.