Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Search in posts
Search in pages
Filter by Categories
15th National Conference of the IAOMFP, Chennai, 2006
Abstracts from current literature
Acne in India: Guidelines for management - IAA Consensus Document
Art & Psychiatry
Association Activities
Association Notes
Award Article
Book Review
Brief Report
Case Analysis
Case Letter
Case Letters
Case Notes
Case Report
Case Reports
Clinical and Laboratory Investigations
Clinical Article
Clinical Studies
Clinical Study
Conference Oration
Conference Summary
Continuing Medical Education
Cosmetic Dermatology
Current Best Evidence
Current Issue
Current View
Derma Quest
Dermato Surgery
Dermatosurgery Specials
Dispensing Pearl
Do you know?
Drug Dialogues
Editor Speaks
Editorial Remarks
Editorial Report
Editorial Report - 2007
Editorial report for 2004-2005
Fourth All India Conference Programme
From Our Book Shelf
From the Desk of Chief Editor
Get Set for Net
Get set for the net
Guest Article
Guest Editorial
How I Manage?
IADVL Announcement
IADVL Announcements
IJDVL Awards
IJDVL Awards 2018
IJDVL Awards 2019
IJDVL Awards 2020
IJDVL International Awards 2018
Images in Clinical Practice
In Memorium
Inaugural Address
Knowledge From World Contemporaries
Leprosy Section
Letter in Response to Previous Publication
Letter to Editor
Letter to the Editor
Letter to the Editor - Case Letter
Letter to the Editor - Letter in Response to Published Article
Letter to the Editor - Observation Letter
Letter to the Editor - Study Letter
Letter to the Editor - Therapy Letter
Letter to the Editor: Articles in Response to Previously Published Articles
Letters in Response to Previous Publication
Letters to the Editor
Letters to the Editor - Letter in Response to Previously Published Articles
Letters to the Editor: Case Letters
Letters to the Editor: Letters in Response to Previously Published Articles
Medicolegal Window
Miscellaneous Letter
Net Case
Net case report
Net Image
Net Letter
Net Quiz
Net Study
New Preparations
News & Views
Observation Letter
Observation Letters
Original Article
Original Contributions
Pattern of Skin Diseases
Pediatric Dermatology
Pediatric Rounds
Presedential Address
Presidential Address
Presidents Remarks
Report of chief editor
Report of Hon : Treasurer IADVL
Report of Hon. General Secretary IADVL
Research Methdology
Research Methodology
Resident page
Resident's Page
Resident’s Page
Residents' Corner
Residents' Corner
Residents' Page
Review Article
Review Articles
Reviewers 2022
Revision Corner
Self Assessment Programme
Seminar: Chronic Arsenicosis in India
Seminar: HIV Infection
Short Communication
Short Communications
Short Report
Special Article
Specialty Interface
Study Letter
Study Letters
Symposium - Contact Dermatitis
Symposium - Lasers
Symposium - Pediatric Dermatoses
Symposium - Psoriasis
Symposium - Vesicobullous Disorders
Symposium Aesthetic Surgery
Symposium Dermatopathology
Symposium-Hair Disorders
Symposium-Nails Part I
Symposium-Nails-Part II
Systematic Review and Meta-Analysis
Systematic Reviews and Meta-analyses
Systematic Reviews and Meta-analysis
Therapeutic Guideline-IADVL
Therapeutic Guidelines
Therapeutic Guidelines - IADVL
Therapy Letter
Therapy Letters
View Point
What’s new in Dermatology
View/Download PDF

Translate this page into:

Observation Letter
87 (
); 103-105

Clear zone phenomenon: A rare phenomenon in ichthyosis with co-existing superficial fungal infection

Department of Dermatology and STD, Lady Hardinge Medical College and SSKH, KSCH, Delhi - 110001, India
Corresponding author: Dr. Pravesh Yadav, Department of Dermatology and STD, Lady Hardinge Medical College and SSKH, KSCH, Delhi - 110 001, India.
This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

How to cite this article: Agrawal M, Yadav P, Yadav J, Chander R. Clear zone phenomenon: A rare phenomenon in ichthyosis with co-existing superficial fungal infection. Indian J Dermatol Venereol Leprol 2021;87:103-105.


Ichthyosis is a common disorder of keratinization, manifesting as noninflammatory scaling, which may range in severity from minimal involvement of a few sites to generalized scaling. Several types of ichthyosis have been classified according to the inheritance, clinical appearance, pathological features and systemic involvement.

Cutaneous dermatophytosis is a common condition with a global prevalence of nearly 20%–25%.1 The most common species implicated for dermatophytosis in India is Trichophyton rubrum.2 There are a handful of reports describing the coexistence of dermatophyte infections in patients with ichthyoses. We hereby report two cases of unusual presentations of dermatophyte infections showing clearing of ichthyotic scaling in patients with congenital ichthyosis.

A 16-year-old Indian male, known case of X-linked recessive ichthyosis (XLRI), presented with itchy lesions in the groin of 20 days duration. Examination revealed generalized light-brown coloured adherent polygonal ichthyotic scales with upturned edges. There were well-defined erythematous scaly plaques in bilateral groins extending to inner thighs suggestive of tinea cruris with a peculiar finding of clear uninvolved zone between the erythematous plaque and ichthyotic skin [Figure 1]. Dermoscopy showed erythema and thicker white scales following the skin creases in the erythematous plaque (probably due to affinity of fungus towards creases due to increased moisture content), surrounded by a clear zone showing neither erythema nor scaling and the adjacent ichthyotic skin showed fine white scales irregularly arranged not respecting the skin creases [Figure 2]. Potassium hydroxide (KOH) mounts and cultures were done from the erythematous plaque, adjacent clear zone and the margin of clear zone with ichthyotic skin. Septate fungal hyphae were demonstrated only from the erythematous plaque. Culture from the erythematous plaque was positive for Trichophyton rubrum while the other two areas were negative. A diagnosis of XLRI with tinea cruris was made.

Figure 1:: Case 1 - Well-defined erythematous scaly plaques in the groins extending to inner thigh (red arrow), adjacent clear uninvolved zone devoid of scaling (white arrow) and generalized ichthyotic fine scales (black arrow)
Figure 2:: Polarized ×10 dermoscopic image from case 1 showing erythema and thick white scales following the skin creases (short black arrows) with adjacent area devoid of erythema or scaling (long black dashed arrow) and ichthyotic skin showing finer white scales irregularly arranged not respecting the skin creases (red arrows) (Dermlite DL4)

Another 19-year-old male having XLRI presented with complaints of round itchy lesions over the chest, abdomen and back of 1 month duration. Examination showed diffuse light-brown scaling all over the body with well-defined discrete as well as coalescing round zones of complete clearance of ichthyotic scales on the trunk, neck, and arms [Figure 3a and b]. KOH examination from the margins of clearing showed fungal elements with culture positive for Trichophyton rubrum.

Figure 3a:: Case 2 - Well-defined discrete as well as coalescing round zones of complete clearance of ichthyotic scales on abdomen
Figure 3b:: Case 2 - generalized distribution of similar clear areas on neck, chest and abdomen

Both patients were treated with oral terbinafine 250mg and topical 1% luliconazole cream once daily along with antihistaminics, emollients and general care for ichthyotic skin. Both of them showed complete clearance of tinea lesions and marked improvement of ichthyosis at 8 weeks follow-up.

Dermatophyte infections may be difficult to suspect in ichthyosis patients or may have unusual presentations.3 There are a number of ways dermatophytosis and the ichthyotic background may interact with each other. Excessive keratin in ichthyosis provides a favorable habitat for fungal growth. Moreover, ichthyosis vulgaris is associated with atopy, which in turn is a risk factor for tinea infections (due to shift from T-helper (Th) 1 to a Th2 response in atopy).4 “Anatopic phenomenon” is a term used to describe the modulation of inflammatory response of one dermatoses by another unrelated cutaneous infection at the same site. 5 The clearance of ichthyotic scaling seen in our cases could be attributed to the arsenal of proteases secreted by dermatophytes aimed at the digestion of the keratin network into assimilable oligopeptides or amino acids. They secrete multiple serine-subtilisins and metallo-endoproteases (fungalysins) formerly called keratinases.6 Production of these enzymes may have led to disintegration of ichthyotic scaling in our cases producing such clear zones. Furthermore, in T. rubrum, the mannans in the cell wall are known to decrease epidermal proliferation.6 This mechanism may also explain reduced scaling observed in our cases. It is difficult to postulate as to why only a clear margin was observed in first case as opposed to complete round clear zones in the latter: probably the extensive involvement in the second case could have led to complete clearing.

In a previously reported case similar to our second case, the authors concluded that the fungus can alter intercellular lipid layers, causing normalization of the cholesterol sulphate-cholesterol ratio correcting the pathology in X linked recessive ichthyosis thereby resolving ichthyotic scaling.3

If further molecular studies are undertaken and the cause is delineated, then extrapolation of clear zone phenomenon can potentially lead to novel treatment modalities for the treatment of congenital ichthyosis.

To conclude, dermatophytic infections must be suspected if cases of ichthyoses present with localized areas of erythema, clear zones and/or increased pruritis.Further research into the underlying pathomechanisms responsible for this clear zone phenomenon may lead to newer therapeutic modalities for ichthyosis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


  1. , . Prevalence of dermatophytic infection and the spectrum of dermatophytes in patients attending a tertiary hospital in Addis Ababa, Ethiopia. Int J Microbiol. 2015;2015:653419.
    [CrossRef] [PubMed] [Google Scholar]
  2. , . Management of tinea corporis, tinea cruris, and tinea pedis: A comprehensive review. Indian Dermatol Online J. 2016;7:77-86.
    [CrossRef] [PubMed] [Google Scholar]
  3. , . Tinea corporis due to Trichophyton verrucosum in recessive, X-linked ichthyosis. Mycoses. 1993;36:319-20.
    [CrossRef] [PubMed] [Google Scholar]
  4. , , , , , , et al. Chronic dermatophytosis in lamellar ichthyosis: Relevance of a T-helper 2-type immune response to Trichophyton rubrum. Br J Dermatol. 2001;145:518-21.
    [CrossRef] [PubMed] [Google Scholar]
  5. . Sparing phenomena in dermatology. Indian J Dermatol Venereol Leprol. 2013;79:545-50.
    [CrossRef] [PubMed] [Google Scholar]
  6. . Dermatophytosis and the immune response. J Am Acad Dermatol. 1994;31:S34-41.
    [CrossRef] [Google Scholar]

Fulltext Views

PDF downloads
View/Download PDF
Download Citations
Show Sections