Psoriasiform lupus vulgaris with 30 years duration

Cutaneous tuberculosis. Part I: Pathogenesis, classification, and clinical features

Tuberculosis is an ancient disease that continues to affect an estimated 10 million people per year and is responsible for 1.4 million deaths per year. Additionally, the HIV epidemic and multidrug resistance present challenges to disease control. Cutaneous tuberculosis is an uncommon, often indolent, manifestation of mycobacterial infection that has a varied presentation. Its diagnosis is challenging, as lesions mimic other, more common conditions and microbiological confirmation is often not possible. Cutaneous tuberculosis can be broadly categorized into multibacillary and paucibacillary forms. Approximately one-third of skin tuberculosis is associated with systemic involvement. By recognizing cutaneous tuberculosis early, dermatologists can play an important role in disease control. The first article in this 2-part continuing medical education series describes the latest epidemiology, microbiology, and pathogenesis of tuberculosis. Furthermore, we review the classification, clinical manifestations, common clinical differentials, and systemic involvement that occur in cutaneous tuberculosis.

Cutaneous sarcoidosis: Lupus pernio and more

Sarcoidosis is a multi-organ disease commonly evident with skin involvement. Cutaneous manifestations occur in about 25% of sarcoid patients and are of two types: histologically specific sarcoidal infiltrations and a cutaneous reaction pattern not containing sarcoidal changes, usually erythema nodosum. Cutaneous plaques, nodules, and tumors, sometimes with disfiguring facial features associated with pain and paresthesia. The disease itself may produce substantial morbidity due to visceral involvement. Advances in therapeutic options include tocilizumab, an IL-6 inhibitor, and tofacitinib, a Janus kinase inhibitor. This review discusses sarcoidosis etiology and pathogenesis, its clinical features, differential diagnosis, and management.

Cutaneous tuberculosis: A great imitator

Tuberculosis (TB) is still prevalent in many developing countries and can pose a new potential threat to global health due to international migration. As an uncommon form of extrapulmonary TB, cutaneous TB is complicated in its clinical manifestation, pathogenesis, and classification. Cutaneous TB can be divided into two major categories, true cutaneous TB and tuberculid, depending on the source of infection, the route of transmission, the amount of bacteria, and the immune state of the host. Clinical manifestations may include patches and plaques (lupus vulgaris, TB verrucosa cutis), macules and papules (acute miliary TB, papulonecrotid tuberculid, lichen scrofulosorum), nodules, and abscesses (erythema induratum of Bazin, tuberculous gumma), erosions, and ulcers (tuberculous chancre, orificial TB, scrofuloderma), mimicking diverse skin diseases. Uncommon localizations such as external genitalia, unusual presentations such as nodular granulomatous phlebitis, and coexistence with other morbidities such as Behçet disease and acne inversa or hidradenitis suppurativa deserve special attention. Treatment of both true and tuberculid cutaneous TB follows the same drug regimens of the World Health Organization's recommendation for treatment of new cases of pulmonary TB. Erythema induratum of Bazin may need longer treatment duration and adjuvants such as dapsone, potassium iodide, doxycycline, and corticosteroids to tackle inflammation. Misdiagnosis and undertreatment in daily practice are likely, and contemplation of this classic great imitator in dermatology is warranted.