Psoriasis: Features on Dermoscopy (Plaque type)

Dermoscopic Pattern of Psoriatic Lesions on Specific Body Sites.
Lallas A. et al. Dermatology. 2014;228(3):250-4. doi: 10.1159/000357914. Epub 2014 Feb 15

-Psoriasis is a condition which affects 2% of the world population.
-Diagnosis is usually clinical, rarely histological.
-Psoriasis can sometimes be difficult to differentiate with other lesions, especially if the lesions are few and localized, scaling is absent and when the nails are uninvolved). Also particularly on the face can be challenging (the differential diagnosis includes seborrheic dermatitis (common dandruff)

-The authors sought to determine dermoscopic features of psoriasis and if different locations might be distinct.
-139 plaque psoriasis lesions were examined on 85 patients located on the scalp, face, folds, palms, soles and genitalia.

RESULTS
-The most common finding was dotted vessels found in 97.1% of examined lesions.
–White scales were present 64.7% of the time
–Vessel distribution was regular in 87.7% of cases and all body sites.
-Frequency of white body scales varied according to location

CONCLUSION

The well-known dermoscopic criteria of psoriasis can also be seen in lesions located on the scalp, face, palms, soles, folds and  genitalia, with the frequency of white scales varying among different body sites.

COMMENT

-Psoriasis is a clinical diagnosis and although sometimes helpful dermoscopy and biopsy (+histological examination) are often not necessary.
-Some would argue that dermoscopy is not useful, but he would only partially agree:
For example, lesions located on the scalp can be differentiated from those caused by seborrheic dermatitis. Click HERE to learn about the dermoscopic differences between seborrheic dermatitis and psoriasis.

Article selection: Prof Dr Jean-Hilaire Saurat – dermatologist. Geneva, Switzerland