diabetes has green discolouration, thickening, and crumbling of multiple toenails, confirmed as onychomycosis due to Trichophyton rubrum.
When multiple nails are involved or infection is extensive, topical treatment is insufficient, and systemic antifungal therapy is required.
Oral terbinafine is the first-line treatment for dermatophyte nail infections, as it has the highest cure rates and good safety profile in most patients
Oral terbinafine 250 mg once daily for 6 weeks (fingernails) or 12 weeks (toenails).
Monitor LFTs
Topical amorolfine – useful for superficial or single-nail infections, but ineffective for multiple nails or deep involvement
Normal ABPI
Normal: 0.9–1.3
Atopic dermatitis(eczema)
Liberal emollients are first-line
Topical steroids for flares:
Mild: Hydrocortisone 0.5–2.5%
If dry skin with frequent itching, and erythema
Moderate: Eumovate (0.05%) or Betnovate RD (0.025%)
If dry skin with frequent itching, and erythema
Potent: Betnovate (0.1%), Cutivate (0.05%)
If widespread dryness, severe itch, erythema and oozing/cracked skin
Very potent: Dermovate (0.05%)
Acne
Suitable first-line options include:
Topical adapalene + benzoyl peroxide (Epiduo)
Topical tretinoin + clindamycin (Treclin)
Topical benzoyl peroxide + clindamycin (Duac)
Chronic plaque psoriasis
Management
Step (1): Potent steroid OD AND vitamin D analogue OD.
Step (2): Vitamin D analogue BD. (Stop potent steroid)
Step (3): Potent steroid BD or coal tar OD
Fever, morbilliform rash with blistering, eosinophilia, neutrophilia, and deranged LFTs around 2 weeks after starting allopurinol for gout. This is suggestive of Drug Hypersensitivity Syndrome (DRESS).
Stevens–Johnson syndrome (SJS) – similar mucocutaneous involvement but occurs within days to 3 weeks of drug exposure and mucosal erosions dominate, not eosinophilia or hepatitis.
Pentoxifylline : it improves microcirculatory blood flow enhancing healing of venous leg ulcers when used alongside compression bandaging.
Acute paronychia is a localised bacterial infection (most commonly Staphylococcus aureus) of the nail fold.
Topical fusidic acid is the treatment of choice for mild cases without abscess formation.
Porphyria cutanea tarda
PCT is caused by a deficiency of uroporphyrinogen decarboxylase, leading to porphyrin accumulation in the skin, making it photosensitive.
Common associations: alcohol, hepatitis, oestrogen therapy, haemochromatosis
Management: Venesection if ferritin raised.
Pellagra
Cause: Deficiency of vitamin B3 (niacin/nicotinic acid).
CFs: 3 D’s:
Diarrhoea
Dementia - depression, memory loss and hallucination
Dermatitis - scaly, pigmented, photosensitive rash most commonly on dorsum of hands, around neck (Casal’s necklace).
Niacin supplementation:
Oral or IV nicotinamide (niacinamide) or nicotinic aci
A: Vitamin B1 (thiamine) deficiency – causes beriberi or Wernicke–Korsakoff syndrome, not photosensitive rash.
B: Zinc deficiency – leads to periorificial and acral rash, alopecia, poor wound healing.
C: Vitamin B12 deficiency – causes megaloblastic anaemia and neuropathy, not diarrhoea and rash.
E: Pyridoxine (B6) deficiency – associated with seborrhoeic dermatitis, glossitis, and neuropathy, not diarrhoea or dementia.
Key points about ABPI:
>0.8 → safe for compression therapy (venous ulcer).
<0.8 → suggests mixed or arterial disease; compression contraindicated.
>1.3 → may indicate calcified, non-compressible arteries (e.g. in diabetes).
According to NICE/CKS guidance, the first-line treatment for moderate to severe inflammatory acne is a topical non-antibiotic agent (e.g. benzoyl peroxide) combined with an oral antibiotic, such as lymecycline or doxycycline.
Pyogenic granuloma – benign vascular lesion that bleeds easily, not ulcerated with violaceous edges.
Pyoderma gangrenosum
Causes: Idiopathic, AI disease, malignancy.
CFs: Small red papule - rapidly enlarges into expanding painful ulcer with violaceous borders.
PCOS-related hirsutism.
First-line pharmacological management:
Topical eflornithine 11.5% cream slows facial hair growth by inhibiting ornithine decarboxylase, an enzyme involved in hair follicle proliferation.
Particularly useful for facial hair in women, either alone or alongside other measures (e.g. laser, mechanical removal, anti-androgen therapy).
Improvement usually seen after 4–8 weeks of continuous use.
Erythroderma features:
Generalised erythema and scaling affecting most of the body (>90%).
Systemic symptoms: fever, lymphadenopathy, dehydration, and risk of high-output cardiac failure.
Causes include exacerbation of psoriasis, eczema, drug reactions, or lymphoma.
Dermatological emergency → requires hospital admission for fluid, temperature, and electrolyte management.
Necrobiosis lipoidica diabeticorum – yellow-brown, atrophic plaques with telangiectasia, typically non-tender and slowly progressive, not ulcerated.
tinea capitis with kerion formation - an inflammatory fungal scalp infection causing a boggy, crusted mass with alopecia.
A kerion is not just a simple fungal infection - it represents a severe inflammatory response, and if not promptly managed, can lead to permanent scarring alopecia.
Erythrasma
Cause: corynebacterium minutissimum.
CFs: Enlarging well-circumscribed flat pink/brown patches in skin folds (axillae/groins) or medial thighs.
Management.
Mild- 1st line: Topical miconazole/clotrimazole.
If extensive 1st line: PO Erythromycin.
Rubella features:
Caused by the rubella virus (a togavirus).
Mild prodrome: low-grade fever, malaise, and lymphadenopathy (especially postauricular, suboccipital, and posterior cervical).
Fine, pink maculopapular rash starts on the face, spreads downward, and resolves within three days (“three-day measles”).
Important due to risk of congenital rubella syndrome if infection occurs in pregnancy.
nodular melanoma -rapidly growing, dome-shaped, black pigmented nodule that bleeds easily
Keratoacanthoma – rapidly growing dome-shaped nodule with a central keratin plug, usually non-pigmented and resolves spontaneously.
