AbstractBackgroundHyperpigmentation of skin, mucous membranes and nails has been described in patients with acquired immune deficiency syndrome (AIDS).Patients and methods7 AIDS patients affected with melasma‐like facial hyperpigmentation were studied. The patients had human immunodeficiency virus infection associated with recurrent mucocutaneous and systemic opportunistic infections. All had a low T4‐CD4 helper cell count and four of them died of severe infections, caused by cytomegalovirus (CMV), mycobacteria (Mycobacterium tuberculosisorAvium) andPneumocystis cariniipneumonia. In these patients the autopsy showed intense infiltration of the adrenal glands. One of them died of Waterhouse‐Friderichsen syndrome; her autopsy showed a massive presence of cytomegalovirus in the adrenal glands.ResultsIn 4 patients dosages of testosterone, cortisol, T3, T4, TSH gave normal results. The level of DHEA‐S was below normal revealing an adrenal insufficiency. The α‐MSH test in 12 patients (4 patients with AIDS and facial hyperpigmentation and 8 volunteers with AIDS, but without pigmented facial lesions) revealed blood levels of α‐MSH above the norm (60.33 pg/ml standard deviation 13.21). The α‐MSH test in 20 healthy subjects revealed a mean value of 44.40 pg/ml (standard deviation 10.47). The biopsy of melasma revealed that melanocytes were present in normal numbers and size with a localized increase of melanin pigment in the basal cell layer.ConclusionAn increased production of ACTH and its derivatives such as α‐MSH pituitary may be the cause of hyperpigmentati