A middle-aged male presented with itching and scaling over the palmar aspect of the left hand for 1 month. There was no history of any previous treatment. Examination of the palmar aspect of the left hand revealed erythema and diffuse white scaling [Figure 1]. Examination of rest of the skin, mucosa, nails and scalp was noncontributory. Dermoscopy (Dinolite AM413ZT) revealed white scales mainly localized to palmar skin furrows and adjoining dermatoglyphics [Figure 2a and d]. Application of immersion fluid revealed dotted vessels in the skin furrows [Figure 2b and e]. KOH examination of the lesional skin scrapings revealed presence of septate hyphae confirming the diagnosis of tinea manuum [Figure 2c].
Figure 1.
Erythema and scaling of the left hand. Note the right hand is not affected
Figure 2.
(a) Polarized dermoscopy showing white scales accentuated in the skin furrows and adjoining dermatoglyphics. [Dinolite AM413ZT; ×200; polarizing]. (b) Polarized dermoscopy with immersion fluid showing the dotted vessels (black arrow) localized to the skin furrows. [Dinolite AM413ZT; ×200; polarizing]. (c) KOH examination of the lesional skin scrapings showing septate branching hyphae (d) Polarized dermoscopy showing white scales accentuated in the skin furrows and adjoining dermatoglyphics. [Dinolite AM413ZT; ×200; polarizing] (e) Polarized dermoscopy with immersion fluid showing the dotted vessels localized to the skin furrows. [Dinolite AM413ZT; ×200; polarizing]
Palmar erythema and scaling is commonly seen in chronic hand eczema, palmar psoriasis, and tinea manuum. Despite a thorough examination, a clinical diagnosis is sometimes not achieved. Histopathology is confirmatory but not feasible in all patients. Dermoscopy can serve as an adjunctive tool to differentiate between these conditions. Dermoscopy of chronic hand eczema reveals sparse white scales, yellow sero-crusts, and orangish dots/globules; and palmar psoriasis shows diffuse white scales with underlying regularly arranged bushy/glomerular capillaries.[1,2] Dermoscopy of tinea manuum shows white scales localized to the skin furrows.[1,3] This case further substantiates the previous findings and in addition highlights the presence of white scales in dermatoglyphics adjoining the skin furrows. The can be explained by the predominant localization of dermatophytes in the furrows and dermatoglyphics. This typical arrangement of scales is different to that seen in psoriasis where a diffuse scaling is seen. The presence of dotted vessels only in the skin furrows in another unique feature noticed in our patient. A possible explanation of this finding is the reactionary vasodilation of vessels in response to inflammatory process induced by dermatophytes. In psoriasis, the dotted vessels are present diffusely in a regular pattern.
To conclude, the dermoscopic findings in tinea manuum seems to be unique and can help differentiate it from psoriasis and eczema, however, further studies are needed to substantiate the findings.
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References
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