|LETTER TO EDITOR
|Year : 2018 | Volume
| Issue : 2 | Page : 93-94
Psoriasis alba: A neglected entity
Niharika Jha1, Bimal Kanish2
1 Department of Dermatology, Dr. B C Roy Post Graduate Institute of Pediatric Sciences, Kolkata, West Bengal, India
2 Department of Dermatology, Christian Medical College, Ludhiana, Punjab, India
|Date of Web Publication||10-Jul-2018|
A-51 Swasthya Vihar, Vikas Marg, New Delhi - 110 092
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Jha N, Kanish B. Psoriasis alba: A neglected entity. Clin Dermatol Rev 2018;2:93-4
Psoriasis is a chronic relapsing inflammatory disorder. The clinical variants of psoriasis include plaque, guttate, inverse (flexural), rupioid, elephantine, pustular, and erythrodermic type psoriasis. Inverse psoriasis involves flexural sites such as inguinal area, axillae, external genitalia, antecubital fossa, popliteal fossa, and rarely the interdigital area of the feet. Interdigital psoriasis of the feet presents as well-demarcated white-colored plaques with a macerated appearance; hence, it is also called as “psoriasis alba” or “white psoriasis.”, This entity was first described by Castellani in 1953 as pseudotinea interdigitalis pedum. The term psoriasis alba or white psoriasis was coined by Waisman in 1961.
A 45-year-old man presented to our dermatology outpatient department with asymptomatic white-colored plaques in toe web spaces of the left foot for 2 weeks. The patient gave a history of asymptomatic red-colored raised lesions on and off on the extremities for the past 2 years. The patient did not seek any medical advice for the lesions on the extremities. There were no comorbidities. On examination, well-defined white-colored plaques having a macerated appearance were noted in the third and the fourth web spaces of the left foot [Figure 1]. Nails of both feet showed discoloration, dystrophy, and subungual hyperkeratosis. Scalp showed seborrhea. Potassium hydroxide examination done from toe web spaces and toenails was negative for fungal elements. Repeat examination was done which was also negative for fungal elements.
|Figure 1: White-colored plaques in the third and fourth toe web spaces having a macerated appearance|
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A diagnosis of psoriasis alba was made, and the patient started on fluticasone propionate ointment (0.05%). The patient responded within 2 weeks of starting the topical therapy [Figure 2].
|Figure 2: Resolution of the lesions upon treatment with topical steroids|
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Psoriasis alba or white psoriasis is a rare type of inverse psoriasis involving interdigital area of the feet. It is mostly asymptomatic but may be associated with mild itching. It is presumed that psoriasis alba lesions are a Koebner phenomenon response to the friction caused by locomotion between the toes.
The clinical presentation of psoriasis alba closely resembles mycological infection and hence, is often misdiagnosed. A diagnosis of psoriasis alba should be considered when a patient presents with well-delimitated, white plaques with macerated appearance in the toe web spaces; the fungal tests are negative. These patients do not respond to conventional antimycotic treatment and should be treated with appropriate steroids.
The Medical Board of the National Psoriasis Foundation recommends low to mid potency topical steroids for the treatment of inverse psoriasis for 2–4 weeks. Other treatment options include tacrolimus, pimecrolimus, or calcipotriol.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/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.
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Castellani A. A brief note on pseudotinea interdigitalis pedum (dermatosis interdigitalis pedum hyperkeratotica). Dermatologica 1954;109:21-4.
Waisman M. Interdigital psoriasis (“white psoriasis”). Arch Dermatol 1961;84:733-40.
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[Figure 1], [Figure 2]