Differential Diagnosis – Forms of Acne
The diagnosis is usually easy, but in some cases, it can be confused with folliculitis, rosacea or perioral dermatitis instead of inflammatory acne.
Acne vulgaris must be differentiated from acne caused by steroids, which is a side effect of oral or topical steroid use. There should also be a distinction made from lupus miliaris disseminatus faciei, as well as verruca plana. Acne-like eruptions are caused by immunosuppressants which are not the same as acne vulgaris. Additionally, acne may co-exist with endocrine disorders. Patients with hyperandrogenism may also have acne and other signs of increased androgen levels, such as hirsutism or abnormal menstrual cycles and acne may also, in some cases, coexist with Polycystic Ovary Syndrome (CPD) or congenital adrenal hyperplasia.
Finally, it is important to differentiate acne from other types, such as cosmetic acne, neonatal acne and acne excoriée (scratched or picked pimples).
Depending on the severity, acne is categorised as follows:
- Inflammatory acne
- Mild Inflammatory Acne– comedones, small papules and pustules
- Moderate Inflammatory Acne – papules-pustules and a few nodules
- Severe Inflammatory Acne – confluent nodules and cysts, a risk of scarring
Severe forms of acne are listed below:
- Acne Fulminans
Acne fulminans is a rare and severe form of acne vulgaris, occurring almost exclusively in young males. Patients suffer from an acute onset of painful, nodular, and occasionally ulcerative acne lesions concentrated on the chest, shoulders, back, and face. Fever, leukocytosis, and musculoskeletal pain may also be present, and the skin lesions usually result in permanent scarring. Osteolytic bone lesions may be present, especially in the clavicle, sternum, and long bones.
- Acne Conglobata
Acne conglobata is a suppurative form of acne vulgaris, which forms pus. It is usually chronic and mostly seen amongst men between the ages of 18 and 30. Its symptoms include cysts, abscesses, and sinus tracts and it often heals, leaving behind cosmetically disfiguring keloidal scars. It is associated with musculoskeletal disorders (synovitis, arthritis, hyperostosis, osteitis) with skin conditions, (palmoplantar pustulosis) and acne conglobata. In addition, sacroiliitis (inflammation of the sacroiliac joint) may also occur, with or without peripheral arthropathy (inflammatory bowel disease) or hidradenitis suppurativa (pimple-like bumps most common underarm or in the groin).
- Pyoderma Faciale
Pyoderma faciale is a relatively rare condition, which occurs with the sudden onset of coalescent fluctuant cysts, nodules, and papules. It is usually confined to the face and occurs exclusively in women between the ages of 15-46. Pyoderma faciale seems to be a severe form of rosacea and most patients develop scars.
- Gram–Negative Folliculitis
This is a bacterial infection, characterised by pustules and cysts. It is assumed that it is likely to occur as a complication resulting from the long-term use of antibiotic therapy administered for acne vulgaris. It is a rare condition, and at the moment, it is not known whether it is more common in men or women. Its clinical characteristics include the sudden appearance of many small pustules, while in some cases nodular lesions are also present in the area around the mouth and nose due to the excessive production of Gram-negative organisms.
Other forms of Acne:
- Αcne Cosmetica
Acne Cosmetica (caused or aggravated by cosmetics/hair care products) affects women over the age of 20 usually those without a history of acne but also those who suffered from acne during puberty during hormonal breakouts. The acne lesions are mainly small, appearing as scattered closed comedones on the face, neck, hairline and scalp. These itchy pink bumps can occur in males and females and develop over a period of weeks or months as the use of hair styling products and lotions can travel to the forehead, cheeks and jaw. Deep-seated nodules and closed comedones with hyperpigmentation may also occur which tend to heal very slowly.
- Pomade Acne
Pomade acne is actually eczema and consists of numerous, closely set closed comedones. The repeated use of various scented ointments or oil for dressing the hair (pomade) can induce acne-like eruptions just like greasy or oily sunscreen preparations and heavy make-up bases can also cause an outbreak.
- Acne excoriée
Acne excoriée is a type of acne most commonly seen in adolescent girls. It is a self-inflicted skin condition, in which the individual feels compelled to squeeze, scratch or pick the acne lesions resulting in scabs and scars. Acne excoriée is often precipitated by emotional stress and anxiety, and sufferers of the condition may also have an undiagnosed psychologic disorder.
- Periorificial Dermatitis
Periorificial or perioral dermatitis is an inflammatory rash characterised by clusters of itchy small red papules, dry flaky skin and a burning irritation which appear around the mouth, eyes and the nose. It is quite common in young women and children, less so in men. The exact cause of periorificial dermatitis is not understood but it may be related to:
- nasal steroids, steroid inhalers, and oral steroids
- cosmetic creams, make-up and sunscreens
- fluorinated toothpaste
- neglecting to wash the face
- hormonal changes and/or oral contraceptives
- topical steroids – corticosteroid medications
A less common variant of periorificial dermatitis is granulomatous dermatitis which is characterised by subcutaneous plaques, annular lesions or nodules predominantly in the lateral walls of the thorax, abdomen and surface of the thighs.