Id reactions

Last Updated: 2023-07-07

Author(s): Anzengruber F., Navarini A.

ICD11: EA88.2

Secondary reactions to fungi (trichophytes, epidermophytid, microsporid) in hyperergic immune state.

In the case of dermatophyte infection, an antigen resorption and finally an antigen-antibody reaction occur in a hyperergic immune situation. From an immunological point of view, this is a type IV reaction. The Id reaction usually occurs far from the focus.

Dyshidrosiform, nodular or multiforme erythema, usually on the extremities.

Lichen trichophyticus is a special form: This is a symmetric, disseminated seeding of follicular papules localised to the trunk.



Mycological diagnosis

Immune testing is not recommended


Very good if the causative mycosis is treated effectively.

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  2. Sorey W. Diagnosis: Dermatophytid reaction (Id reaction). Commentary. Clin Pediatr (Phila). 2009 Apr;48(3):335. 
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