BL (Borderline lepromatous)
Skin lesions are multiform, vary in size, are thickened or infiltrated, reddish or brownish in color, often numerous and widespread. They may be bilateral in distribution, but not symmetric. The surface of the lesions are usually smooth and shiny with ill-defined edges. Patchy areas of diffuse infiltration may be noted. Sensory impairment varies from minimal to total anaesthesia, especially in the center of immune areas; or anaesthesia involving hands and feet but usually asymmetric. Bacteriologic smears are positive and the Mitsuda reaction is negative.
Lepromatous Leprosy (LL)
LLs (Sub-polar lepromatous )
In the sub-polar type of lepromatous leprosy (LI in older terminology), skin lesions closely resemble those of LLp leprosy; however, one or a small number of residual, asymmetric borderline lesions may be detected; also asymmetric nerve damage and nerve enlargement may be demonstrable; eyebrows may be intact. Bacteriologic smears are positive and Mitsuda reaction, negative.
LLp (Polar lepromatous)
In the polar type of lepromatous leprosy, the skin lesions are widespread, generalized and symmetric, in the form of diffuse thickening usually with erythema or hyperpigmentation. The affected parts appear smooth and shiny in the early stages; in advanced disease, nodulations and corrugations of the skin. Macular lesions are small, ill-defined, slightly hypochromic or faintly erythematous; are fairly numerous; slightly infiltrated, more or less bilaterally distributed. Papular or nodular lesions are seen in advanced disease, commonly over areas already infiltrated; some may break down into ulcerations; nerve involvement occurs later in the disease, is bilateral and symmetric resulting in "glove and stocking" type of anaesthesia. Deformities are numerous and varied in the form of loss of eyebrows, collapse of the nose, gynecomastia, atrophy of the muscles of the hands and feet, clawing of the fingers and toes, contractures, and trophic ulcerations. Bacteriologic smears are always highly positive and Mitsuda reaction is negative.
Histoid Leprosy
This is a special manifestation of lepromatous leprosy characterized by papules or nodules in the skin or subcutaneous tissue. Majority develop as a manifestation of relapse, with a high percentage associated with DDS-resistance; but may arise without prior chemotherapy. The lesions are usually shiny, reddish or brownish in color, developing over areas of healed infiltration or other areas previously unaffected, and may occur in unusual sites of the skin surface. Bacteriologic smears are highly positive and the Mitsuda reaction is negative.
Erythema Nodosum Leprosum (ENL)
The skin manifestation of this lepra reaction (Type 2) consists of often tender, transient erythematous nodules of various size, superficial or deep-seated in the dermis. Usually dome-shaped with shiny surface and ill-defined margin. They may undergo pastulation and ulceration, and if multiple, may show different stages of development. They appear on any skin surface, but more commonly on face, arms and thighs.
