Dowling-Degos disease, hidradenitis suppurativa and arthritis in mother and daughter

Conflict of interest: none declared. Dowling–Degos disease (DDD) is a rare genodermatosis manifesting in young adults as acquired, reticulate, symmetric pigmentary macules of the flexural areas.1 Abnormal follicular epithelial proliferation has been speculated to be the cause of simultaneous occurrence of DDD and hidradenitis suppurativa (HS).2 The association of DDD, HS and arthritis in two generations has not, to our knowledge, been reported previously. A 48‐year‐old woman presented with a 20‐year history of hyperpigmentation of the flexures and discharging nodules over the axillae and gluteal regions. For the past 2 years, she had had arthritis affecting the right shoulder and both knees. Cutaneous examination showed hyperpigmented macules in a reticulate pattern over the neck, inframammary area, axillae, cubital fossae (Fig. 1a) and groin. Pigmented macules were also present over the buccal mucosa (Fig. 1b) and palate. She had lesions of HS in the axillae (Fig. 1c) and groin. There was painful restriction of abduction of the right shoulder joint. Plain radiographs of the involved joints were within normal limits. The patient refused any further tests.