Lepromatous Leprosy Diagnosis and Differential Diagnoses

Clinical Presentation

The American College of Dermatology notes that lepromatous leprosy presents with multiple erythematous papules and nodules or diffuse infiltration of the face, hands, and feet in a bilateral and symmetrical distribution that progresses to skin thickening, with lesions showing porcelain-white to erythematous coloration and eventual development of nodules (lepromas) that may ulcerate 1, 2
Lepromatous leprosy is characterized by multiple lesions with bilateral symmetrical distribution affecting face, hands, and feet, according to the World Health Organization 1, 2
The disease presents with papules, nodules (lepromas), and diffuse infiltration rather than discrete plaques, as stated by the National Institute of Dermatology 1
Progressive skin thickening with loss of normal skin architecture is a key feature of lepromatous leprosy, as noted by the American Academy of Dermatology 1, 2

Cutaneous leishmaniasis produces ulcerative or nodular lesions that can mimic lepromatous nodules, but these lesions are typically painful and lack sensory loss, and demonstrate Leishmania organisms on tissue smear or biopsy rather than acid-fast bacilli, according to the Centers for Disease Control and Prevention 1
Sarcoidosis manifests with nodular skin lesions and can involve peripheral nerves, but demonstrates negative acid-fast bacilli on skin smears, elevated serum angiotensin-converting enzyme (sensitivity 60%, specificity 70%), and shows non-caseating granulomas on biopsy without nerve predilection, as stated by the American Thoracic Society 1
Cutaneous lymphomas can produce nodular or infiltrative skin lesions mimicking lepromatous leprosy, but histopathology reveals atypical lymphocytes rather than granulomas with acid-fast bacilli, according to the National Cancer Institute 1
Tuberculoid leprosy presents with one or few well-demarcated, hypopigmented, and anesthetic skin lesions with active spreading edges and clearing centers, contrasting sharply with the multiple bilateral lesions of lepromatous disease, as noted by the World Health Organization 1, 2

The American College of Physicians recommends assessing lesion distribution, with bilateral symmetrical involvement strongly suggesting lepromatous leprosy 1, 2
Testing for sensory loss is crucial, as anesthesia in lesions is pathognomonic for leprosy and absent in most mimics, according to the National Institute of Neurological Disorders and Stroke 1
Full-thickness skin biopsy is the gold standard for diagnosis, showing histiocytic infiltration with acid-fast bacilli in lepromatous form, as stated by the American Academy of Dermatology 1, 2
Serum ACE level is elevated in sarcoidosis (60% sensitivity, 70% specificity), according to the American Thoracic Society 1
Tissue culture or PCR can identify Leishmania species if leishmaniasis is suspected, as noted by the Centers for Disease Control and Prevention 3