GPAtlas🧭 When to suspect
Suspect pityriasis versicolor (PV) in a patient presenting with multiple, well-demarcated, oval, finely scaly macules that are either lighter (hypopigmented) or darker (hyperpigmented) than the surrounding skin. PV is an overgrowth of Malassezia – a lipophilic yeast that lives harmlessly on everyone's skin – so it is not contagious, and the older term "tinea" versicolor is a misnomer (it is not a dermatophyte infection).
The rash favours the upper trunk, back, neck and upper arms (the seborrhoeic areas), and is classically more obvious after sun exposure because the affected patches fail to tan. It is usually asymptomatic, though mild itch can occur. It is commonest in young adults and is provoked by heat, humidity, sweating and immunosuppression, so it often recurs each summer or after a sunny holiday.
The two key skills in primary care are to recognise it clinically (distinguishing it from vitiligo, seborrhoeic dermatitis and other causes of dyspigmentation) and to manage expectations – treatment clears the yeast quickly, but the discolouration takes months to settle, and relapse is the rule rather than a sign of failure.
| Differential | How to tell it apart from PV |
|---|---|
| Vitiligo | Complete depigmentation (not just lightening), no scale, often symmetrical or periorificial/acral; Wood's lamp shows sharp bright blue-white. |
| Seborrhoeic dermatitis | Greasy yellowish scale with erythema and itch in seborrhoeic sites (scalp, nasolabial folds, eyebrows, central chest); shares the Malassezia link but looks inflamed. |
| Pityriasis rosea | Herald patch, collarette scale, "Christmas-tree" distribution along skin lines; self-limiting over 6–12 weeks. |
| Pityriasis alba | Children with atopic tendency; ill-defined, faintly scaly hypopigmented patches, usually on the face. |
| Post-inflammatory hypo-/hyperpigmentation | Follows prior inflammation or injury; no active scale and no fluorescence. |
| Tinea corporis | Annular plaque with a raised, scaly active edge and central clearing; microscopy shows dermatophyte hyphae, not the spore-and-hyphae mix of PV. |
Source: DermNet · British Association of Dermatologists
🔒 Sign up free to read the full topic
You're viewing a free preview. Create a free account to unlock the rest.
Sign up free →Sample topics are open to everyone in the Free Sample Bundle.