Table 2.

Reported cases of metformin-induced fixed-drug eruption.

No.	Author/year	Age (year old)/sex	Dermatologic manifestation	Histopathology	Naranjo scale [13]	Treatment
1	Monroe/2010 [16]	41/female	Round, purplish-brown, targetoid macules ranged in size from 1 to 3 cm on the lips, face, and arms and some edematous lesions	Interface changes, scattered necrotic keratinocytes, and epidermal pigmentary incontinence	NA∗	Discontinuation of metformin oral antibiotics, corticosteroids, and acyclovir had no effect
2	Steber et al./2016 [14]	56/female	Small, round, erythematic, pustular lesions on palms and soles	NA	Naranjo = 8	Discontinuation of metformin
3	Ramirez Bellver et al./2017 [11]	86/male	Round/oval, erythematous pruritic macules, and patches, located on his lower limbs mostly on his buttocks, forearms, and hands	Cutaneous hemophagocytosis/superficial and deep perivascular dermal infiltrate interface dermatitis and necrotic keratinocytes/necrotic keratinocytes concentrated at the acrosyringium/deep dermal infiltrate composed of histiocytes	Naranjo = 5	Discontinuation of metformin oral prednisone for 2 weeks had no effect
4	Sharma et al./2017 [17]	47/male	Round/oval erythematous macules, tender palpable purpura patches on the lower limbs, lower back, and buttocks	NA	Naranjo = 6	Discontinuation of metformin oral prednisone cream of synthetic glucocorticoid (fluticasone) had no effect
5	Togawa et al./2019 [18]	46/male	Skin rashes on the lower left thigh and the back of the body after taking metformin and also after metformin hydrochloride TE	NA	NA	Discontinuation of inactive ingredients of metformin
6	Al Masri et al./2021 [10]	58/female	Itching and burning sensation over the right leg accompanied by the appearance of blisters, ulcerations, and erythema after starting metformin and also after gliclazide, vildagliptin, empagliflozin, and liraglutide	Lichenoid drug eruption	NA	Discontinuation of metformin
7	Our case	43/male	Multiple well-defined erythematous to violaceous plaques with a central dusky appearance in association with bulla formation over the chest, extremities, genitalia, and lips	Vacuolar interface dermatitis, apoptotic keratinocytes, and pigment incontinence associated with eosinophils infiltration	Naranjo = 10	Discontinuation of metformin

^∗ NA = Not available.