Itching is a common complaint among patients infected with HIV and may cause significant morbidity and embarrassment. Although idiopathic HIV-pruritus has been described, it is probably less common than was previously thought. In most patients, a careful history and physical examination will show that a dermatosis accounts for their pruritus. Dry skin, seborrheic dermatitis, eczema, psoriasis, pruritic papular eruption, staphylococcal folliculitis and prurigo nodularis are frequently encountered in these patients. These common dermatoses, drug eruptions, several rarer conditions and systemic causes of itching should be excluded before diagnosing idiopathic HIV-pruritus. Treatment should be directed to the underlying skin problem and may be supplemented with sedating antihistamines. Phototherapy is a safe and effective therapeutic modality for many pruritic dermatoses as well as for idiopathic pruritus.