Definition. An acute inflammatory disease of the skin, characterized by the formation of nodular swellings, chiefly on the tibial regions.
Symptoms. This affection is often classified with erythema multiforme and may be associated with other forms f multiforme, but clinically it is usually a distinct affection. Unna pointed out that the difference between this condition and erythema multiforme rests upon the fact that the former never widens concentrically, never produces bullae and never exhibits annular vesicles. The average attack begins with moderate fever, articular pains, headache and malaise, but these symptoms are not constant, except the pain in the legs and the tenderness over the tibia where the eruption usually appears on the second or third day, although occasionally it may be located on other parts. The lesions occur in crops of three or four symmetrical, round or oval, nodular swellings which may vary in size from a cherry to a hen’s egg, and merge in an ill-defined way into the surrounding tissues which may appear somewhat edematous. The nodules are firm but sore to the touch, and for one or two days after their advent are attended with sensations of aching, burning or stinging; later they soften and appear to slightly fluctuate, but never rupture or suppurate. At first of a bright red or pink and white color, they become a dusky red, and passing through the ordinary changing colors of a bruise, “black and blue,” they disappear in a week to ten days. New crops may prolong the whole course for two to five weeks, but unlike the other forms of erythema, recurrences are rare.
Etiology and Pathology. This disease usually afflicts those under thirty years of age, principally youths and young adults, and is much more frequent in males. Many authorities believe that it is a genuine rheumatic process, but personally O believe that erythema nodosum is a toxic affection produced by a number of poisons, f which the rheumatic infection is the commonest. Gastrointestinal disorders, acute fevers, bad sanitation and many drugs have predisposed toward it. Microscopic examination reveals considerable dilatation of the blood and lymph vessels and some cell infiltration. Serous exudation is present throughout the entire cutis; even the subcutaneous tissue will show the nodes so affected.
Diagnosis. It may be necessary to differentiate this condition from a bruise, abscess, syphilitic gumma and erythema induratum, but its symmetrical distribution, course, tenderness and colour changes should be diagnostic.
Prognosis and Treatment. The former is favourable and the latter consists of rest with elevation of the legs, simple diet and locally lead water and laudanum applications. Here again the indicated remedy is far superior to any antirheumatic physiological dosing. The following may be studied: Am.mur., Apis, Aurum mur., Belladonna, Juglans cin., Kali brom., Rhus tox., Sal. acid, Sulphur acid.