Dermatophytids

From WikiMD's Wellness Encyclopedia

Overview of dermatophytids, their causes, symptoms, and treatment


Dermatophytids, also known as id reactions, are secondary skin eruptions that occur in response to a primary fungal infection, typically caused by dermatophytes. These reactions are not due to the direct spread of the fungus but are rather an allergic response to the fungal antigens.

Pathophysiology[edit | edit source]

Dermatophytids are a type of hypersensitivity reaction that occurs when the immune system reacts to antigens from a primary fungal infection. The primary infection is usually a dermatophytosis, such as tinea pedis (athlete's foot), tinea corporis (ringworm of the body), or tinea capitis (scalp ringworm). The immune response leads to the development of a rash at a site distant from the original infection.

Clinical Presentation[edit | edit source]

Patients with dermatophytids typically present with:

  • A pruritic (itchy) rash that appears on areas of the body not directly affected by the fungal infection.
  • The rash may consist of small vesicles, papules, or erythematous patches.
  • Common sites for dermatophytids include the hands, arms, chest, and face.

The rash is usually symmetrical and can be quite itchy, causing significant discomfort.

Diagnosis[edit | edit source]

Diagnosis of dermatophytids involves:

  • Clinical examination and history taking to identify a primary fungal infection.
  • Potassium hydroxide (KOH) preparation of skin scrapings from the primary infection site to confirm the presence of dermatophytes.
  • The absence of fungal elements in the dermatophytid lesions themselves, as these are not caused by direct fungal invasion.

Treatment[edit | edit source]

The primary approach to treating dermatophytids is to address the underlying fungal infection. This may involve:

  • Topical or oral antifungal medications, such as terbinafine, itraconazole, or fluconazole.
  • Symptomatic treatment of the dermatophytid rash with topical corticosteroids to reduce inflammation and itching.

Once the primary fungal infection is effectively treated, the dermatophytid reaction typically resolves on its own.

Prognosis[edit | edit source]

The prognosis for patients with dermatophytids is generally good, as the condition resolves with appropriate treatment of the primary fungal infection. However, if the primary infection is not adequately treated, the dermatophytid reaction may persist or recur.

Also see[edit | edit source]




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Contributors: Prab R. Tumpati, MD