Erythema nodosum, a painful disorder of the subcutaneous fat, is the most common type of panniculitis. Generally, it is idiopathic, although the most common identifiable cause is streptococcal pharyngitis.Erythema nodosum may be the first sign of a systemic disease such as tuberculosis, bacterial or deep fungal infection, sarcoidosis, inflammatory bowel disease, or cancer.rythema nodosum nodules vary from 0.4 to 4 inches (1 to 10 cm) in diameter and are poorly demarcated, reflecting their subcutaneous anatomic location (Table 11â4; Figure 1) . Pretibial involvement is most common, although the extensor surfaces of the forearm, the thighs, and the trunk also may be affected.
xeric - being deficient in moisture; deserts provide xeric environments. 1  hydric - having or characterized by excessive moisture; a hydric habitat. 2  mesic - having or characterized by moderate or a well-balanced supply of moisture; mesic habitats.
1. an agent that mediates a specific effect. 2. an organ that produces an effect in response to nerve stimulation. allosteric effector an enzyme inhibitor or activator that has its effect at a site other than the catalytic site of the enzyme.(Ä­-fÄkâ²tÉr).. A peripheral tissue that receives nerve impulses and reacts by contraction (muscle), secretion (gland), or a discharge of electricity (electric organ of certain bony fishes). 2. A small metabolic molecule that, by combining with a repressor gene, depresses the activity of an operon.