Drug -induced Skin Disorders (pack)

Question 1

Excessive sensitivity to sunlight

Answer 1

UVA and UVB exposure can occur on a sunny or cloudy day. It is usually localised on all uncovered skin and isnt dose dependent,
Appear after weeks/months and looks eczematous, lichenoid, urticarial, bullous or purpuric eruption.

Causative DRUGs: griseofulvin, sulphonamides, sulphonylureas, thiazide diuretics, amiodarone, nalidixic acid, tetracyclines and chlorpromazine.

Question 2

Pigmentation changes

Answer 2

Can be hyper-pigmentation or hypopigmentation, it can be widespread or localised (e.g., skin stain after using silver dressings, enhanced melanin production with or without increase in melanocytes

Causative DRUGs: bleomycin sulfate, a cytotoxic antibiotic).

Question 3

Nail changes

Answer 3

Causative DRUGs:
Chemotherapy (white, depression, and separation from the nailbed, beau’s lines or interruption of normal growth),

Minocycline (blue-black stain) or

Potassium permanganate (brown stain).

Question 4

Hair changes

Answer 4

Total loss of hair (alopecia) where drug interference in the hair growth phase,

Partial/Complete temporary loss of hair, e.g., cytotoxic drugs (chemo)(reversible but after few weeks from ceasing treatment unless V high dose,),

Delay in hair growth (or the shedding cycle faster than growth cycle), retinoid therapy and danazol therapy (Hirsutism / Hypertrichosis in women or change in hair pattern in men).

Question 5

Drug-induced exanthems (rash/spots/blotches on skin caused by virus)

Answer 5

widespread rash, erythema (redness, <90% of BSA), morbilliform (resemble measles) or maculopapular (a mixture of flat and raised areas)

Causative DRUGs:
Chloroquine, ampicillin and isoniazid.

Question 6

Urticarial rash

Answer 6

Or hives - red, itchy weals) and angioedema (more serious, in the deep soft tissues – swelling, mostly notable on the face)
Examples - Penicillin and irritant contact dermatitis.

Question 7

Pruritus (itchy skin)

Answer 7

Centrally mediated, e.g., side effects of opioids and tramadol,
Resolved by ceasing medication only.

Question 8

Fixed drug eruptions

Answer 8

Same spot every time the same medication is administered,
Causative DRUGs:. dapsone, metronidazole, aspirin.

Question 9

Acneiform eruptions

Answer 9

Drug mediated acne eruptions,
Causative DRUGs: anabolic steroids

Question 10

Psoriasiform eruptions

Answer 10

Worsening of pre-existing psoriasis, Cuasative DRUGs: Lithium and β-blockers.

Question 11

Lichenoid eruptions

Answer 11

Resolve by ceasing the drug.
They appear as flat mauve lesions but they can be scaly and confluence (cell covers another surface),
Causative DRUGs: gold salt, imatinib, interferon-α.

Question 12

Erythema multiforme

Answer 12

Eruption red, raised skin areas, the centre blisters in severe cases. Limbs and mucous membranes are involved but not trunk.
Occurs 2 weeks after starting the drug,
Causative DRUGs: allopurinol and macrolide antibiotics.

The condition is reversible when stopping the drug.

Topical corticosteroids can be used for limbs,
Paracetamol for pain and fever and Topical treatment can be used for the mouth, eye and genital symptoms.

Question 13

Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN)

Answer 13

2 conditions can be life-threatening. They are mucocutaneous drug hypersensitivity syndromes where blistering and epidermal sloughing occur. SJS causes <10% of BSA skin detachment and TEN causes >10% of BSA skin detachment

Causative DRUGs: lamotrigine, doxycycline and co-trimoxazole, allopurinol, spirilactone

Drug withdrawal and supportive treatments include systemic steroids or ciclosporin, IV immunoglobulin, infection management, thermoregulation, maintenance of fluid balance, skin care and eye care.

Question 14

Drug reaction with eosinophilia and systemic symptoms

Answer 14

Presents as an extensive, inflammatory, maculo-papular exanthem with lymph node enlargement, abnormal LFTs and haematological abnormalities, raised eosinophil count, or presence of atypical lymphocytes. There may also be renal, pulmonary or cardiac involvement

Causative DRUGs: vancomycin, sulphasalazine, antiretrovirals.

It can be fatal (10%), long latency characteristics, 2-8 weeks from drug commencement.

Question 15

Acute generalised exanthematous pustulosis

Answer 15

Characterised by widespread monomorphic pustules and fever.

Patients generally unwell and have excessive heat and fluid loss.

This condition can be treated by topical potent steroids.

Causative DRUGs: lamotrigine, metronidazole, amoxicillin.

Question 16

Lupus erythematosus

Answer 16

Characterised by seroconversion to antinuclear antibody positive.

Patient may recover after drug withdrawal but may leave residual formed antibodies. Skin eruption is a butterfly-shaped rash on the face, photosensitive erythema on dorsal hands and neck and annular lesions on limbs.
Treated by infliximab and etanercept which block TNF-α.

Question 17

Vasculitis

Answer 17

Characterised by inflammation of the vessel walls (lower limbs).

Drug withdrawal and systemic steroids or IV immunoglobulin can be used in its treatment.