From the Guidelines
Eosinophilia is primarily caused by allergic reactions, parasitic infections, and certain medications, with allergic disorders being the most common cause, occurring in about 80% of cases, as noted in the study by 1. The causes of eosinophilia can be broadly categorized into infectious and non-infectious etiologies. Infectious causes include parasitic infections, such as strongyloidiasis and schistosomiasis, which are common in returning travelers and migrants, as highlighted in the study by 1. Non-infectious causes comprise allergic reactions, autoimmune disorders, and certain medications, including antibiotics and NSAIDs, as mentioned in the study by 1. Some key points to consider when evaluating the causes of eosinophilia include:
- Allergic conditions, such as asthma, eczema, and hay fever, are common triggers of eosinophilia, as part of the body's immune response, as noted in the study by 1.
- Parasitic infections, particularly those involving worms like hookworms, roundworms, and schistosomiasis, often lead to elevated eosinophil counts, as the body attempts to fight the invaders, as highlighted in the study by 1.
- Medications, such as antibiotics, NSAIDs, and certain antipsychotics, can induce eosinophilia as a side effect, as mentioned in the study by 1.
- Autoimmune disorders, like eosinophilic granulomatosis with polyangiitis and hypereosinophilic syndrome, directly involve eosinophil dysfunction, as noted in the study by 1.
- Some malignancies, particularly certain leukemias and lymphomas, can cause eosinophilia through abnormal production of cytokines that stimulate eosinophil growth, as mentioned in the study by 1. It is essential to accurately diagnose the underlying cause of eosinophilia to establish an appropriate treatment plan, as emphasized in the study by 1.
From the Research
Eosinophilia Causes
Eosinophilia is a condition characterized by an elevated count of eosinophils in the bloodstream. The causes of eosinophilia can be diverse and include:
- Parasitic infections, such as those caused by helminthic parasites 2
- Allergic diseases, including allergic drug eruption, urticaria, allergic contact dermatitis, atopic dermatitis, and eczema 3, 4, 5
- Autoimmune diseases, such as bullous pemphigoid 5
- Connective tissue diseases and rheumatologic diseases 3
- Primary eosinophilia, including hypereosinophilic syndrome 3, 4
- Malignant states, such as certain types of cancer 3, 4
- Drug-induced eosinophilia 4
- Eosinophilic skin diseases, including eosinophilic cellulitis, granuloma faciale, eosinophilic pustular folliculitis, recurrent cutaneous eosinophilic vasculitis, and eosinophilic fasciitis 5
Specific Causes
Some specific causes of eosinophilia include:
- Parasitic infections, which can cause tissue-invasive helminthic parasites to trigger eosinophilia 2
- Allergic processes, which are the most common cause of eosinophilia in North America 4
- Idiopathic hypereosinophilic syndrome, which must be ruled out when an absolute eosinophil count of more than 1.5 x 10(9)/L persists for longer than 6 months 4
- Underlying hematological disorders, which may be associated with certain rare eosinophilic dermatoses, such as eosinophilic fasciitis and eosinophilic cellulitis 5