DermNet

The authoritative resource about dermatology and the skin: dermnetnz.org The world's most popular skin website - written and edited by Dermatologists worldwide.

03/08/2025

Clascoterone or cortexolone 17α-propionate is a topical treatment targeting the hormonal pathogenesis of acne vulgaris.

It is postulated that clascoterone competes with androgens such as dihydrotestosterone (DHT) for androgen receptors, inhibiting the downstream signalling pathways of androgen receptor-regulated gene transcription in sebaceous glands and dermal papilla cells responsible for acne pathogenesis.

Clascoterone is currently available as a 1% (10mg/g) cream. A thin, uniform layer to the affected area once to twice a day: morning and evening is recommended.

See our newly updated page on this treatment for more.

27/07/2025

Scleroedema presents with symmetrical hardening and thickening of the skin. The affected areas are firm and woody plaques, sometimes slightly red or brown and often with a ‘peau d'orange’ (orange-skin) appearance. The face may appear expressionless and there can be difficulty opening the mouth.

There are three types of scleroedema. All three types of scleroedema can restrict movement, but otherwise seldom have serious consequences. Occasionally swallowing and speech can be affected and other organs involved – eyes, tongue, parotid gland, muscles, joints and heart.

Read more on our DermNet page.

23/07/2025

Capillaritis is classified according to its appearance. It is characterised by tiny red and brown dots, described as cayenne pepper spots. These may be scattered over a body region or group together to form a flat red patch, which becomes brown and then slowly fades away over weeks to months. Capillaritis can disappear within a few weeks, recur from time to time, or persist for years.

16/07/2025

Sarcoidosis is a multisystem disease characterised by granulomas in various organs. Characteristically, these are non-caseating epithelioid granulomas (a pathological description distinguishing sarcoidal granulomas from the caseating or cheese-like granulomas seen in tuberculosis).

Skin involvement is present in up to one-third of patients.

About 30% of patients with cutaneous sarcoidosis have no involvement of other organs.

Lesions may be non-specific or specific based on the presence or absence of non-caseating granuloma on histopathologic examination. Read about sarcoidosis on our DermNet page here: https://dermnetnz.org/topics/sarcoidosis

13/07/2025

Ichthyosis is a disorder of cornification, characterised by persistently dry, thickened, 'fish scale' skin. There are at least 20 varieties of ichthyosis, including inherited and acquired forms. Read all about it on our DermNet page today.

09/07/2025

Have you seen patients with pleomorphic dermal sarcomas? Read about the condition here: https://dermnetnz.org/topics/pleomorphic-dermal-sarcoma

06/07/2025

Herpetic whitlow can be diagnosed clinically based on history and appearance of the lesions.

Viral cultures or a Tzanck smear can be used to confirm the diagnosis.

Ballooning multinucleated giant cells and eosinophilic inclusion bodies are seen on the Tzanck smear. A bacterial swab can also be taken if secondary or concurrent bacterial infection is suspected.

Read more about the condition our DermNet page here: https://dermnetnz.org/topics/herpetic-whitlow

02/07/2025

A viral wart is a very common benign lesion caused by infection with human papillomavirus (HPV). Viral warts can be classified by site as being cutaneous or mucosal as the HPV types are quite distinct.

A cutaneous wart is also called a verruca or papilloma, and warty-looking lesions of any cause may be described as verrucous or papillomatous.

Read more about warts here: https://dermnetnz.org/topics/viral-wart

29/06/2025

Remember to join thousands of HCPs for free access to DermNet PRO by signing up to the waitlist today—now with highly sophisticated search functionality.

Don’t miss out! Join today: https://pro.dermnetnz.org/

25/06/2025

Acanthosis nigricans affects < 1% of Caucasians. In the United States, the estimated prevalence is 13.3% among African Americans, 5.5% among Latinos, and 34.2% among Native Americans.

It affects both males and females of all ages, with people < 40 years of age typically being more affected. Acanthosis nigricans was found in 18.2% of children and 19.5% of adults in a cross-sectional study (n=1730) in the United States. Those diagnosed with AN were twice as likely to have type 2 diabetes compared to those without (35.4% vs. 17.6%).

Rarely, AN may present as a paraneoplastic syndrome in the setting of internal malignancy. Such malignant AN tends to develop abruptly and to occur in patients who are middle-aged and not obese.

Read more on our updated DermNet page here: https://dermnetnz.org/topics/acanthosis-nigricans

22/06/2025

Dyshidrotic eczema (pompholyx) is an itchy, chronic, recurrent, often symmetric eruption on the palms of hands, fingers, and soles of the feet. It is characterised by small, deep-seated, 1–2 mm fluid-filled vesicles on these sites, which resolve after several weeks with scaling.

Dyshidrotic eczema (pompholyx) can lead to:

1) Secondary infection, eg, bacterial infection with Staphylococcus aureus or Streptococcus pyogenes producing lymphangitis and cellulitis

2) Paronychia and nail dystrophy if adjacent or proximal to the nail fold

3) Physical and psychological disability

Read more on our DermNet page here: https://dermnetnz.org/topics/dyshidrotic-eczema

18/06/2025

Subcutaneous fat necrosis of the newborn - have you heard of this condition or seen it in your practice? Swipe through the carousel to learn more or find out more on our new Dermnet page.

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DermNet NZ has become a world renowned resource all about the skin. The website is owned by the DermNet New Zealand Trust. It has been HON (Health-on-The-Net) certified since 1996 and is in continuous development to provide information about the skin over any desktop or mobile web browser.

Our mission is to make authoritative information about the skin accessible to anyone in the world with an internet connection.

Dr Amanda Oakley, DermNet's founder, was most recently honoured by being appointed by Her Majesty The Queen as a Companion of the New Zealand Order of Merit in recognition of her services and contribution to Dermatology. She was also awarded the Google Technology Service in the Charitable Sector's Lifetime Service Award at the New Zealand Charities Technology Awards in March 2017 and was a finalist in two categories the New Zealand Woman of Influence awards in June, 2017.