Dermatological Disorders

Question 1

Mention the most common dermatoses in Nigeria.

Answer 1

1. Atopic dermatitis (Eczema)
2. Tinea versicolor
3. Acne
4. Contact dermatitis
5. Urticaria (Hives)
6. Seborrheic dermatitis
7. Psoriasis
8. Vitiligo
9. HPV infections (Warts)
10. Cutaneous adverse drug reactions (Drug-induced skin disorder)

Question 2

What are drug-induced skin disorders?

Answer 2

These are the inevitable consequences of modern drug therapy which affect the skin.

Question 3

It is often difficult to determine the cause of drug-induced eruptions. Why?

Answer 3

i. Almost any drug can affect the skin; its hard to tell which one
ii. Unrelated drugs may produce similar reaction
iii. The same drug may produce different reaction in different patients
iv. Some drug reactions are hard to tell apart from other skin conditions, such as acne, psoriasis and eczema.
v. Excipients contained in medication, may be the culprit rather than the drug itself.

Question 4

How are drug-induced skin eruptions diagnosed?

Answer 4

i. Patient history
ii. Time relation of onset of reaction to commencement of drug

Question 5

Mention 3 classes of drug-induced skin disorders.

Answer 5

1. Drug reactions causing changes to skin function
2. Mild drug-induced skin disorders
3. Severe drug-induced skin disorders

Question 6

Give 4 examples of drug reactions causing changes to skin function.

Answer 6

1. Abnormal photosensitivity: may be phototoxic or photoallergic
   Examples: Amiodarone, Griseofulvin, Sulphonamides, NSAIDs, Nalidixic acid
2. Nail changes e.g.
   i. Leukonychia (white nails): from treatment with chemo agents like Cyclophosphamide, Doxorubicin, Vincristine
   ii. Beau’s lines
3. Pigmentary changes e.g.
   i. Brown pigments: from oral contraceptives
   ii. Blue-back colouration: from Tetracycline
4. Hair changes e.g.
   i. Alopecia: cytotoxic drugs , interferons
   ii. Hirsutism: Anabolic steroids, Minoxidil, Tamoxifen

Question 7

Give 4 examples of mild drug-induced skin disorders.

Answer 7

i. Drug-induced exanthems (widespread rash): Any drug is capable of causing this, but it is commonly caused by:
- antibiotics e.g. sulphonamides, ampicillin, isoniazid
- anticonvulsants e.g. phenytoin, carbamazepine
- antimalarials e.g. chloroquine
Most drug-induced exanthems begin within 7 days of drug commencement and are considered Type IV (delayed) hypersensitivity

ii. Urticaria and Angioedema: can be allergic or non-allergic e.g. penicillins, vancomycin, sulphonamides.

iii. Pruritus

iv. Fixed drug eruptions: one or more inflamed patches that occur on the same cutaneous or mucosal sites each time the patient is exposed to the offending drug. e.g. Ampicillin, Sulphonamides, Dapsone

Question 8

Give 2 examples of severe drug-induced skin disorders.

Answer 8

i. Erythema multiforme: An eruption of “target-like”, concentric red and pale lesion, which may in severe cases, have central blistering. It typically occurs on the arms, rather than trunk, but may affect mucous membranes, such as the eyes, mouth or genital tract.
Examples: Allopurinol, Nevirapine, Barbiturates, Carbamazepine, Cimetidine, Dapsone.

ii. Stevens-Johnson syndrome (SJS) and Toxic epidermal necrolysis (TEN): life-threatening mucocutaneous drug hypersensitivity syndromes characterised by blistering and epidermal sloughing.
High loss of heat and fluid and increased risk of infection due to damaged barrier function can cause serious morbidity similar to extensive burns.
Examples: Allopurinol, Antiretrovirals e.g. Nevirapine, Carbamazepine, Co-trimoxazole, Dapsone.

All of the above conditions are idiosyncratic and immunologically mediated.

Patients with HIV or Systemic lupus erythematosus (SLE) are at a higher risk of developing SJS/TEN.

Question 9

________ should be the first intervention in cases of suspected drug eruption.

Answer 9

withdrawal of the likely offending drug

Question 10

Mention 4 general methods to provide systematic relief and limit drug eruptions.

Answer 10

i. Emollients e.g. shea butter, cocoa butter, petrolatum, mineral oil
ii. Soap substitutes e.g. E45 wash, SebaMed wash
iii. Oral histamines e.g. Loratidine, Cetrizine, Ketotifem
iv. Mild topical corticosteroids e.g Triamcinolone, Clobetasol

Question 11

Mention 2 medications used in the management of vitiligo.

Answer 11

1. Pimecrolimus cream (Calcineurin inhibitor)
2. Ruxolitinib cream (J Janus-activated tyrosine kinase (JAK) 1 and 2 inhibitor)

Question 12

Mention medications used in the management of Fungal skin/nail/hair infections.

Answer 12

i. Ketoconazole cream, gel or shampoo
ii. Itraconazole tablets, capsules, oral solution
iii. Selenium sulfide lotion or shampoo