Reticular erythematous mucinosis is a rare and persistent form of primary idiopathic mucinosis, often referred to as plaque-like cutaneous mucinosis or midline mucinosis. It presents with reticulate patches or erythematous plaques with predilection for the anterior and posterior trunk. Affected patients are frequently asymptomatic. Pruritus or burning sensations were reported after exposure to the sun. The aetiology remains obscure; its pathogenesis is poorly understood, particularly in immunocompromised patients such as HIV-infected patients. The disease associations are not uniformly documented. Antimalarial agents significantly improve and shorten the course of the disease. We report a case of a 31-year-old African woman with underlying HIV infection who displayed the classical clinical and histological features of reticular erythematous mucinosis. This condition is rare among the HIV-infected patients, particularly in those of African descent, in whom lichen myxoedematosus/scleromyxoedema variants and acral persistent papular mucinoses were most frequently reported. The higher incidence of photosensitivity in HIV-infected individuals including the patients with skin of colour may play a potential role in reticular erythematous mucinosis. Its relationship with lupus erythematosus and photosensitivity in the context of HIV infection is discussed. To the best of our knowledge, this is the first reported case of reticular erythematous mucinosis in an African HIV-infected patient. This case highlights the need for diagnostic awareness in cases presenting with erythematous plaques and patches in a net-like pattern developing on the midline and sun-exposed areas of the trunk.