Tinea incognita

Cause

The use of a topical steroid is the most common cause. Frequently, a combination topical steroid and antifungal cream is prescribed by a physician. These combinations include betamethasone dipropionate and clotrimazole (trade name Lotrisone) and triamcinolone acetonide and clotrimazole. In areas of open skin, these combinations are acceptable in treating fungal infection of the skin. In areas where the skin is occluded (groin, buttock crease, armpit), the immunosuppression by the topical steroid might be significant enough to cause tinea incognita to occur even in the presence of an effective antifungal.

Diagnosis

Clinical suspicion arises especially if the eruption is on the face, ankle, legs, or groin. A history of topical steroid or immunosuppressive agent is noted. Confirmation is with a skin scraping and either fungal culture or microscopic exam with potassium hydroxide solution. Characteristic hyphae are seen running through the squamous epithelial cells.

Treatment

The removal of the offending topical steroid or immunosuppressive agent and treatment with a topical antifungal is often adequate. If the tinea incognita is extensive or involves hair bearing areas, treatment with a systemic antifungal may be indicated.

Notes

References

References

1. (2018). "Textbook of Medical Mycology". Jaypee Brothers Medical Publishers Ltd.
2. (2020). "Andrews' Diseases of the Skin: Clinical Dermatology". Elsevier.
3. "What is tinea incognita?".
4. (March 2017). "A Closer Look at the Term "Tinea Incognito:" A Factual as Well as Grammatical Inaccuracy.". Indian Journal of Dermatology.
5. Continued application results in expansion of the fungal infection which appears unrecognisable. Occasionally, [[secondary infection]] with [[bacteria]] occurs with concurrent [[pustule]]s and [[impetigo]].Habif, T. P. (1995) ''Clinical Dermatology''. Mosby, 3rd ed.; pp. 41-42.