Drug eruptions (dermatitis medicamentosa). Drug eruptions may mimic nearly the entire range of dermatoses of other causes. One of the commonest forms is the exanthematic, whose lesions are usually erythematous and edematous. Common causes of drug eruptions include ampicillin, cephalosporins, semisynthetic penicillins, and barbiturates. We have just illustrated cases that were morbilliform. Illustrated here are cases clinically resembling erythema multiforme.
Fordyce’s condition. The face abounds in sebaceous glands. Normally their distribution stops sharply at the junction of the skin and vermilion of the lips. Commonly, however, ectopic sebaceous glands are found within the lips under the vermilion and sometimes within the oral mucosa of the lips and even in the buccal mucosa. The condition is harmless and may have been present long before the patient or parents became aware of it. No treatment is required or available.
Dermatofibroma. These are benign dermal nodules that represent a focal proliferation of fibroblasts; the overlying epidermis is slightly thickened. Their occurrence is not unusual in children and adolescents. Dermatofibromas are firm and may be black, red, brown, or flesh-colored. Their diameter generally ranges from 0.5 to l.5 cm, although they may occasionally be larger. Dermatofibromas may be solitary or multiple, and they develop either spontaneously or after minor trauma to the skin, such as an insect bite. Most are asymptomatic but sometimes may be painful on palpation. A very useful diagnostic maneuver is executed by exerting lateral pressure on the lesion. The skin overlying a dermatofibroma will frequently dimple. Dermatofibromas require surgical treatment only when they are of cosmetic concern to the patient. However, biopsy analysis is occasionally required in order to confirm the diagnosis and to differentiate it from more serious disorders.