Angioedema - Cellulitis DDx
Angioedema can be caused by medications, foods, or be idiopathic. Drug-induced angioedema can be associated with urticaria, but it can occur alone with deeper tissue swellings being the only manifestation. The subcutaneous tissues, airway, and gastrointestinal tract are all possible sites of involvement. Angiotensin-converting enzyme (ACE) inhibitors are a common cause, with angioedema occurring even months after therapy has been started. Other causes include aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, radiocontrast, fibrinolytic agents, and estrogens including oral contraceptives.
Idiopathic angioedema is three or more episodes of recurrent angioedema with no apparent cause after comprehensive medical evaluation.
Non-histaminergic angioedema, which occurs in about 1 of 20 cases, does not present with hives, unlike allergic and idiopathic forms of angioedema. Similar to hereditary angioedema and to ACE inhibitor-induced angioedema, where there is bradykinin involvement, non-histaminergic angioedema is not responsive to antihistamines or corticosteroids.
Angioedema seen in the heritable angioedema syndrome lasts longer, is not responsive to standard antihistamine therapy, and usually will not have urticarial lesions. Familial forms begin in adolescence; they have autosomal dominant inheritance and are related to disorders of complement regulation. Episodes of angioedema are often precipitated by surgery or accidents. There are symptoms, such as abdominal pain, that are not a feature of typical angioedema. See Hereditary angioedema for further discussion.
Acquired angioedema is typically the result of a lymphoproliferative disorder or autoimmune, neoplastic, or infectious disease. Acquired C1 esterase inhibitor deficiency may result from the formation of autoantibodies against C1 esterase inhibitor or persistent low-level activation of C1q by anti-idiotypic antibodies in patients with B-cell lymphoproliferative disorders. Symptoms of acquired angioedema closely resemble those of hereditary angioedema.
The swelling of angioedema is often more marked than that of cellulitis. Conversely, erythema is a less prominent feature. Unlike cellulitis, angioedema almost always occurs bilaterally. In angioedema, there may also be a history of exposure to a known inciting factor.
T78.3XXA – Angioneurotic edema, initial encounter
41291007 – Angioedema
- Insect bite reactions
- Contact dermatitis
- Cellulitis or erysipelas
- Pasteurella multocida infection
- Vibrio vulnificus infection
- Systemic causes of peripheral edema (congestive heart failure, nephrotic syndrome)
- Necrotizing fasciitis
- Eosinophilic cellulitis (Wells syndrome)
- Serum sickness / serum-sickness-like drug eruption
- Acral erythema