Fixed Drug Eruptions in Patients with Darker Skin

00:01 Welcome to our lecture on fixed drug eruption (FTE).

00:07 Dermatological manifestations of drug reactions that often occur in the same location on re-exposure to a drug are called fixed drug eruptions.

00:19 They are seen in 2 to 5% for inpatients, and roughly about just more than 1% in outpatients. Fixed drug eruptions account for as much as 16 to 21% of all cutaneous drug reactions. The female-to-male ratio is the same one is to one.

00:41 It is a type IV hypersensitivity reaction and is usually due to oral medications, and the following are some of the drugs that can cause fixed drug eruptions.

00:53 Less commonly, it could be due to topical or intravaginal medications, as well as herbal supplements that have also been implicated in the literature.

01:05 There are four major types of fixed drug eruptions: localized pigmented type, localized bullous type, mucosal type, and generalized bullous or nonbullous type.

01:17 Focusing on localized type, one gets violaceous well-demarcated patch with a dusky border. This is typically seen in patients with dark pigmented skin.

01:32 The violaceous, poorly demarcated patch is seen within a newly erythematous border.

01:39 And as mentioned before, the erythema may be very subtle in skin of color. The differential diagnosis of this type is post-inflammatory hyperpigmentation, which usually arises after a skin disorder or injury.

01:55 Lichen planus pigmentosa is also a differential for this type of fixed drug eruption, the localized bullous type one gets localized blisters and erosions on specific areas. The differential is bullous pemphigoid.

02:15 As we know, it's an autoimmune blistering disorder with usually larger blisters.

02:21 Bullous insect bite is another differential which develops as an inflammatory response to insect venom or saliva, which is deposited during an insect bite on the skin. The third type is a mucosal type.

02:35 It's a well-defined erythematous patch with plaques at times with or without blisters.

02:43 The differential diagnosis is mucosal pemphigoid.

02:47 This is seen more commonly and with irregularly shaped erosions or ulcers in the mouth. It affects one or more mucosal surfaces could be the mouth, the eyelids or the genital area.

03:03 The last type is a generalized bullous or nonbullous type of fixed drug eruption.

03:08 It's a rare presentation of fixed drug eruption with lesions covering more than 10% of the body surface area.

03:19 The generalized bullous or nonbullous type differential includes Stevens-Johnson syndrome or toxic epidermal necrolysis.

03:27 And as we have seen in our lecture before, it usually involves a larger skin body area and there is always mucosal involvement.

03:38 The diagnosis of a fixed drug eruption needs a detailed drug history and proper physical examination. Skin biopsy may be necessary to exclude the differentials that we have mentioned and oral challenge test, which involves introducing small incremental amounts of the drug to see if the patient reacts in a similar way to the offending drug. Patch testing has also been used in some patients.

04:10 Management includes discontinuation of suspected medication.

04:14 We usually ask the patients to bring all their medication so that the doctor can look through them and see which is the most likely offending drug, and this way you are able to avoid the implicated medication.

04:29 Topical or systemic corticosteroids or antihistamines can be used to minimize inflammation and the itch, which may be associated with fixed drug eruption. If the secondary infection, antibiotics may be indicated, a generalized bullous fixed drug eruption requires intensive care or admission in a burns unit, although this is a rare manifestation of fixed drug eruption.